• Dr. Peter Seiler
  • University of Minnesota
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Mazen Farhood

Dec. 7, 2015 – More efficient aircraft can be designed by reducing weight and structure in the wings and fuselage. This makes the aircraft more flexible leading to dynamics that change rapidly with flight condition. Linear parameter varying (LPV) systems are a useful framework to model these rapidly changing dynamics. This talk will focus on two theoretical challenges. First, it is possible to model the dynamics of flexible aircraft with high fidelity fluid/structure models. A method will be described to construct reduced-order, control-oriented models. Second, the uncertainty in the aeroelastic models must be considered in the control design. The remainder of the talk will focus on analysis and synthesis tools that address this model uncertainty.

Biography:

Dr. Seiler received his Ph.D. from the University of California, Berkeley in 2001. His graduate research focused on coordinated control of unmanned aerial vehicles and control over wireless networks. From 2004-2008, Dr. Seiler worked at the Honeywell Research Labs on various aerospace and automotive applications including the redundancy management system for the Boeing 787, sensor fusion algorithms for automotive active safety systems and re-entry flight control laws for NASA's Orion vehicle. Since joining the University of Minnesota in 2008, Dr. Seiler has been working on fault-detection methods for safety-critical systems as well as advanced control of wind turbines and flexible aircraft.

  • Dr. Craig Woolsey
  • Aerospace and Ocean Engineering
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Nov. 30, 2015 – Interest in biomimetic flight has been motivated by the “pull” from security applications, such as unobtrusive mobile surveillance, and the “push” from scholars seeking new multiphysics research challenges. Consider the variety of prefixes which signify the unqualified governing principles: unsteady fluid/structure interaction; nonlinear, nonautonomous dynamics; underactuated control. The presentation will describe ongoing efforts to optimize the morphology and gait of biologically inspired aquatic and atmospheric vehicles. Although system models are typically time-varying and high-dimensional, geometric control and averaging theory can provide simplified models that are amenable to design optimization and control.

Biography:

Craig Woolsey is a Professor in Virginia Tech’s Aerospace and Ocean Engineering Department. The principal aim of Prof. Woolsey’s research is to improve performance and robustness of autonomous vehicles, particularly ocean and atmospheric vehicles. The theoretical focus is nonlinear control, particularly energy-based methods for mechanical control systems. Prof. Woolsey is a past recipient of the NSF Career Award and the ONR Young Investigator Program Award and served as the founding Director of the Virginia Center for Autonomous Systems (www.unmanned.vt.edu), an interdisciplinary research center within Virginia Tech’s College of Engineering.

Nov. 23, 2015 – Classes are not in session from November 21st to November 29th in observation of Thanksgiving Break

  • Mr. Brian Danowsky
  • Systems Technology, Incorporated
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania and Dr. Kevin Wang

Nov. 16, 2015 – High fidelity modeling of aeroservoelastic aircraft with both rigid body and flexible dynamics is achieved using Computational Fluid Dynamics coupled with Computational Structural Dynamic (CFD/CSD) models. This modeling approach has advantages over potential flow-based modeling approaches in directly capturing unique dynamic aspects of vehicles that have significant coupling between rigid body and flexible dynamics. Full order CFD/CSD models require significant computational processing and memory, making them unsuitable for control design. An efficient approach has been developed that generates input-to-output reduced order state space models directly from these high order models. These reduced order models represent significant computational savings in both time and memory. They are ideal for control design and they capture the critical dynamic aspects associated with these highly coupled vehicles. This approach is applied to a small flexible aircraft designed specifically for aeroservoelastic research. The advantages and unique aspects of this approach are highlighted.

Biography:

Mr. Brian Danowsky (M.S. in Aerospace Engineering, Iowa State University, 2004; B.S. in Aerospace Engineering, Iowa State University, 2002). Mr. Danowsky is a Principal Research Engineer at Systems Technology, Incorporated, where he has been since 2007. His main areas of expertise are dynamic modeling and simulation of air vehicles, flight control and guidance systems, robust stability and control, aeroelasticity, aeroservoelasticity and aerodynamic parameter estimation. Flight vehicles of study at STI have consisted of high altitude lighter-than-air vehicles as well as high speed fighter aircraft. Mr. Danowsky is currently and has been the principal investigator for numerous government programs in the areas of aeroelasticity and aeroservoelasticity for NASA, the US Air Force, the US Navy, and the US Army. Research objectives for these programs consist of incorporating active feedback control into very high fidelity coupled computational fluid dynamic and computational structural dynamic models, reduced order modeling capability, aeroelastic uncertainty analysis, adaptive aeroservoelastic suppression, nonlinear aeroservoelastic free-play analysis, and buffet load measurement. Mr. Danowsky received the Dave Ward Memorial Lecture Award from the Aerospace Control and Guidance Systems Committee in 2013 for technical contributions to aeroservoelastic control. He is an Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA) and is an active member of the AIAA Atmospheric Flight Mechanics Technical Committee. He is also a member of the Tau Beta Pi and Sigma Gamma Tau national honor societies.

  • CDR Josh Dittmar
  • United States Navy
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Robert Canfield

Nov. 9, 2015 – Abstract:

Billed as the answer for fulfilling Dull, Dirty and Dangerous missions, Unmanned Aircraft Systems (UAS) are a relatively mature technology currently used for military and homeland security purposes and poised for rapid growth and transition to support many other government and commercial sectors. This brief provides an overview of UAS, addresses seven UAS problem areas, and describes the challenges in UAS Design, Test and Employment with an emphasis on integrated system design and human systems integration. An additional case study is presented on the first combined employment of UAS during Operation Unified Protector, the NATO mission concerning the Libyan Civil War in 2011.

Biography:

Commander Josh “Tree” Dittmar is currently Government Flight Test Director for the MQ-8B Fire Scout Unmanned Aircraft System. A graduate of the Naval Academy and the Air Force Institute of Technology, he has been involved in the UAS operational and developmental test since 2009. Reporting to VX-1 at NAS Patuxent River in 2009, CDR Dittmar served as the UAS Department Head, leading the operational test efforts for four UAS test teams including MQ-4C Triton, RQ-21A Blackjack, Cargo Resupply UAS, and MQ-8B Fire Scout. In 2011, he reported to NATO Air Command in Izmir, Turkey where he served as an Exercise Planner and UAS expert. Qualified in the MQ-8B Fire Scout as an Air Vehicle Operator, CDR Dittmar previously served in two P-3C Orion squadrons (VP-9 and VP-10), flying over 2,000 flight hours as a Naval Flight Officer in support of Counter Drug Operations from Puerto Rico and Panama, Anti-Submarine Operations from Iceland, Operation Allied Forge from Sicily, and Operations Iraqi Freedom and Enduring Freedom from Iraq, Qatar and Bahrain. In 2012, he led a test team to complete the CNO-mandated MQ-8B integration with the Advanced Precision Kill Weapon System II (APKWS II), the first forward-firing weapons integration of a Naval UAS and currently leads efforts to test the Navy’s first rotary-wing UAS radar integration. He has 8 wonderful kids and 1 amazing wife, and flies a 3DR Solo quadcopter in his spare time as a drone hobbyist.

  • Mr. Daniel Miller
  • Lockheed Martin
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Nov. 2, 2015 – Abstract: Tomorrow's air vehicles will need high functionality and aerodynamic performance with an unprecedented level of requirements on advanced component integration. An overview of promising flow control technologies will be discussed in the context of addressing these next-gen challenges.

Bio: Mr. Daniel Miller has led numerous air vehicle innovations in the areas of propulsion, aerodynamics, thermodynamics, flight controls, high energy laser integration, and composite structures. These technologies have been used on major programs including the F-35, F-22, C-130, and are being evaluated for next-generation platforms.

Based on his technical accomplishments, Daniel has earned the prestigious position of Senior Technical Fellow in the Air Vehicle Sciences & Systems organization of the Skunk Works®. Daniel's accomplishments include 24 U.S. and European patents granted with 20 additional patents pending; more than 50 technical publications; co-editor and co-author of an AIAA textbook on flow control; co-instructor of an AIAA short course series at 10 conferences; and 20 invited lectures hosted by academia, government, and professional societies.

Daniel has received the highly coveted Corporate NOVA award, which is the Lockheed Martin Corporation’s highest award for technical achievement, and the LM Aeronautics Company AeroStar award. In addition, AIAA, ASME, SAE, and academia have honored him with various awards for his superior contributions.

Daniel holds both a Master of Science and a Bachelor of Science degree in Mechanical Engineering from the University of Wisconsin. He is an Associate Fellow of AIAA.

  • Mr. Richard "Tad" Chichester
  • Lockheed Martin
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Robert Canfield

Oct. 26, 2015 – The Lockheed Martin F-35C is the US Navy’s newest carrier-based fighter aircraft, one of the three-variant F-35 family of single-seat, single-engine, all-weather, stealth multirole fighter aircraft currently in production for multiple US armed services and partner countries. Drop testing of a full scale structurally complete aircraft was performed to verify compliance with the US Navy structural integrity and flight certification requirements leading up to flight test and ship trials of the jet. Results from the full scale drop tests are used to clear the aircraft for high sink rate arrested landings in flight test and to provide evidence for final structural certification of the F-35C. The drop test program consisted of 47 simulated shipboard landings for a variety of design touchdown conditions at specified aircraft attitudes, sink rates, and aircraft store configurations. A summary of the F-35C drop test program will be presented outlining design requirements for shipboard landings, test objectives, test setup, conduct, and results, including correlation with analytical predictions.

Biography:

Richard “Tad” Chichester is Senior Manager of the F-35 Structures Technologies group, responsible for design loads and criteria, structural dynamics, flutter and aeroelasticity, vehicle-level finite element analysis, and mechanical/electrical systems integrity on the F-35 Program. He has been with Lockheed Martin and General Dynamics in Fort Worth, TX for over 36 years, working in various roles on the F-111, F-16, F-16XL, A-12, F-35, and other advanced design programs. He graduated from Virginia Tech in 1979 with a B.S. in Aerospace and Ocean Engineering, and holds a M.S. degree in Engineering Management from Southern Methodist University.

  • Dr. Pei Zhong
  • Duke University
  • 145 Goodwin Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Kevin Wang

Oct. 21, 2015 – Abstract: Mechanisms and processes of kidney stone fragmentation by weakly focused shock waves

Oct. 19, 2015 –

  • Dr. Stefano Brizzolara
  • MIT-iShip, Innovative Ship Design Lab,Massachusetts Institute of Technology
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Abstract: High Speed Ships present numerous design challenges and research topics of interest to naval architects. Conventional free surface hydrodynamics is complicated by new important phenomena such as cavitation, ventilation and free surface rupture (spray wave- breaking) which interact together. The relative importance of these topics will be introduced through a series of design examples, originating from 15 years of personal experience in fast vessel design and academic research into ship hydrodynamics by numerical/experimental methods. The presentation will touch at first some initial designs of semi-displacement Deep-V monohulls used for the first series of largest-ever fast ferries (140m, 40+ knots) that lead the way to the recent LCS-1 series of US Navy ships, increasing the design speed to transitioning onto planing hulls with steps and partial ventilation of the bottom where the characterization of the air/water mixture flow is essential to accurately solve the problem. A new type of advanced planing craft, intensively studied in the last two years, has demonstrated the ability to reduce the drag of conventional planing hulls by more than 30%, ensuring an optimal behavior in waves at the same time. An outlook onto newest super-cavitating (ventilated) surface-piercing hydrofoils will be finally given.

Bio: Stefano Brizzolara, MSc in Naval Architecture and Marine Engineering with honors at Genova University, PhD in numerical hydrodynamic for ship design, has been a professor in the Department of Naval Architecture Marine and Electrical Engineering of the Univ. of Genova where he initiated the course in Numerical Hydrodynamics for Ship Design in 2003. He joined the Massachusetts Institute of Technology (MIT) in 2011 first as Peabody Visiting Associate Professor and now as head of the new Innovative Ship Design Lab (MIT-iShip) in the Mechanical Engineering Department. His current research deals with innovative design of high speed vessels and maritime related topics as Assistant Director for Research at the MIT Sea Grant. He leads and has lead several research projects for the Office of Naval Research of the US Navy, DARPA, the Italian MoD and the Maritime Industry dealing with hydrodynamics of advanced vessel and propulsion systems. He is author of more than 100 scientific papers and holder of four patents.

  • Dr. Vigor Yang
  • Georgia Institute of Technology
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Oct. 12, 2015 – Unsteady flow oscillations in combustion devices, commonly known as combustion instabilities, were discovered in rocket and air-breathing engines in the late 1930s. Since then, combustion instabilities have plagued most, or in fact practically all, engine development programs. Indeed, because of the high density of energy release in a volume having relatively low losses, conditions favor excitation and sustenance of flow oscillations in any combustion chamber intended for use in a propulsion system. This seminar will provide an overview of combustion instabilities in four different types of propulsion systems (solid rocket, liquid rocket, gas turbine, and ramjet/scramjet engines). Emphasis will be placed on the present understanding of underlying mechanisms, and contemporary research needs and challenges. Various research issues in acoustics, fluid mechanics, and chemistry related to oscillatory combustion in practical systems will be discussed. Both passive and active control techniques will be covered. Applications of numerical simulations, analytical methods, and experimental diagnostics to combustion instability studies will be addressed.

Biography:

Dr. Vigor Yang is the William R. T. Oakes Professor and Chair of the School of Aerospace Engineering at the Georgia Institute of Technology. He has published numerous papers and 10 comprehensive volumes on aerospace propulsion and energetics. He has received several publication and technical awards from the American Institute of Aeronautics and Astronautics (AIAA) and American Society of Mechanical Engineers (ASME), including the Air-Breathing Propulsion Award (2005), the Pendray Aerospace Literature Award (2008), the Propellants and Combustion Award (2009), the Worcester Reed Warner Medal (2014), and the JANNAF Interagency Propulsion Lifetime Achievement Award (2014). Dr. Yang was the editor-in-chief of the AIAA Journal of Propulsion and Power (2001-2009) and the JANNAF Journal of Propulsion and Energetics (2009-2012). He is currently an editor of the Aerospace Book Series of the Cambridge University Press (2010-). A member of the U.S. National Academy of Engineering, Dr. Yang is a Fellow of the AIAA, ASME, and Royal Aeronautic Society. He was a Vice President of the AIAA (2012-2015).

Oct. 5, 2015 –

  • Dr. Tiangang Cui
  • ACDL lab, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Heng Xiao

Abstract:
Inverse problems convert indirect measurements into useful characterizations of the unknown parameters of a physical system. Parameters are typically related to indirect measurements by mathematical models, which are complicated and expensive to evaluate numerically. Available indirect data are often limited, noisy, and subject to natural variation, while the unknown parameters of interest are often high-dimensional, or infinite-dimensional in principle. Solution of the inverse problem, along with model prediction and uncertainty assessment, can be cast in a Bayesian setting and thus naturally characterized by the posterior distribution over parameters conditioned on the data.

In this talk, I will present a set of likelihood-informed methods for overcoming the two central challenges in posterior exploration: algorithmic scalability to high-dimensional parameters and computational efficiency of numerical solvers. Our methods identify the intrinsic dimensionality in both the parameter space and the model space by exploiting the synergy between various information sources and model structures. The resulting reduced subspaces yield computationally fast posterior exploration tools that are scalable to high-dimensional parameters. Numerical examples in groundwater and atmospheric remote sensing are used to demonstrate the efficacy of our methods.

Bio:
Tiangang Cui is currently a postdoc associate at the ACDL lab, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology. He obtained his Bachelor in Applied Mathematics, Master in Engineering Science and PhD in Engineering Science all from the University of Auckland, New Zealand. His research interest lies in large-scale inverse problems, data assimilation, Bayesian statistics and scientific computing, with applications in subsurface, environmental fluids and imaging.

Sept. 28, 2015 –

  • Dr. Xiaolin Li
  • Department of Applied Math and Statistics
    State University of New York at Stony Brook
    Stony Brook, NY 11794
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Heng Xiao

Abstract:
We use the front tracking platform for a spring-mass system to model the dynamic motion of parachute canopy and risers. The canopy surface is represented by a triangulated surface mesh with preset equilibrium state. The model is shown to be numerically convergent under the constraints that the summation of points masses is constant and that both the tensile stiffness and the angular stiffness of the spring conform with the material's Young modulus and Poisson ratio. This flexible mechanical structure is coupled with the incompressible Navier-Stokes solver through the ``Impulse Method''. Complex validation simulations conclude the effort via drag force comparisons with experiments.

Bio:
Dr. Xiaolin Li obtained his Ph. D. degree from Columbia University and is now a professor at the Applied Mathematics and Statistics Department of the State University of New York, Stony Brook. His research interests include computational fluid dynamics problems with dynamically moving front, interface and boundary. He is the major developer of the front tracking library, a sophisticated software tool to handle interface motion with changing geometry and topology. He has applied the front tracking method to the study of fluid interface instabilities, phase transition problems and fluid structure interactions. He is the PI or co-PI of many research grants from Department of Energy and Department of Defense. He has been the visiting research fellow of Naval Research Lab, Edwards AFB, Los Alamos National Lab and Oak Ridge National Lab. He is also a visiting faculty member of the National Taiwan University and Nanjing University of Aeronautics and Astronautics of China. His current research project on parachute modelling and simulation has been supported by the US Army Research Office.

  • Dr. Earl Duque
  • Intelligent Light
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Sept. 21, 2015 – Accelerating the Post-Processing of Large Scale Unsteady CFD Applications via In Situ Data Reduction and Extracts
By: Dr. Earl P.N. Duque
Manager of the Applied Research Group, Intelligent Light
Rutherford, NJ
epd@ilight.com

Abstract: Writing, storing, moving and post-processing vast unsteady datasets can interfere with an engineer’s interpretation and reporting of results. This seminar will present ongoing research to develop new methods designed to extract and reduce large unsteady CFD derived volumetric data. In-Situ data extraction whereby sub-setting and segmenting the volume data using data extraction and analysis libraries directly integrated within the solver codes themselves is the first step. To further reduce the amount of unsteady CFD extract data written to disk, methods such as Proper Orthogonal Decomposition may be used to reconstruct the solution data within a given error band. This seminar will present preliminary research and how CFD practitioners can use these techniques to analyze their large-scale CFD solutions.

  • Dr. Nam-Ho Kim
  • University of Florida
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Seongim Choi

Sept. 14, 2015 – Reliability-based design optimization has been developed in order to provide safety for complex engineering systems, such as aircraft, automotive, bridges and nuclear power plants. These systems are not only made safe by good design, but through an array of risk-reduction measures (i.e., safety measures) during their lifecycle, such as building-block tests during development, quality control during manufacturing, inspection and maintenance during operation,and accident investigation to find a possible cause of the accident. Current design practices for minimum risk or high reliability only account for uncertainty information available at the design stage without considering uncertainty reductions through safety measures, hence falling short of achieving optimal solutions in terms of cost and safety.

The objective of this presentation is to formulate safety measures as uncertainty reduction tools and to quantify their effects on the system reliability. The presentation includes (1) comparison between repeating tests and exploring design space for uncertainty reduction and detecting un-recognized failure modes, (2) uncertainty propagation in building-block process and the effect of tests, (3) determining optimal tolerances for trade-off between performance (weight) and manufacturing cost, (4) utilizing health monitoring system to predict the remaining useful life with a desired level of reliability, and (5) cost-effectiveness of accident investigation to improve system safety.

Biosketch: Dr. Nam-Ho Kim is currently a Professor in the Department of Mechanical and Aerospace Engineering at the University of Florida. He graduated with a Ph.D. in the Department of Mechanical Engineering from the University of Iowa in 1999 and worked at the Center for Computer-Aided Design as a postdoctoral associate until 2001. His research interests include design under uncertainty, prognostics and health management, nonlinear structural mechanics and design sensitivity analysis. He has been authors and co-authors of five books and more than two hundred journal articles and conference proceedings. He is an Associate Fellow of American Institute of Aeronautics and Astronautics and a member of the Editorial Boards of Journal of Mechanical Design, Structural and Multidisciplinary Optimization and International Journal of Reliability and Safety.

  • Dr. Jon V Larssen
  • 737 MAX Community Noise Lead Engineer, Boeing Commercial Airplanes
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport

Aug. 31, 2015 – Abstract: With airports, surrounding communities, and regulatory agencies adopting stricter rules to address noise concerns related to aircraft traffic, there are strong incentives for airlines to operate a fleet of quiet airplanes. Consequently, over the past 50 years improvements in engine technology have significantly reduced aircraft community noise levels. This presentation provides an introduction to aircraft noise in context of the regulatory environment to which commercial airplane manufacturers must respond, along with a high level overview of how the Boeing Company utilizes technology demonstrator programs to mature and implement environmental technologies benefiting new airplanes and the communities in which they operate.

Bio: Jon Larssen received his dual Bachelor of Science degrees in Aerospace and Ocean Engineering from Virginia Tech in 2001, and a Ph.D in Aerospace Engineering in 2005 focusing on low speed turbulence under the direction of Dr. W. Devenport at Virginia Tech. Upon graduation Dr. Larssen joined the Acoustic Research and Technology branch of Boeing Commercial Airplanes in the Seattle area where he participated on multiple airplane programs from wind tunnel campaigns through certification flight testing. Currently Dr. Larssen is the lead engineer for the 737 MAX Community Noise group responsible for ensuring noise certification of the newest members of the 737 family of aircraft.

  • Dr. Eric Paterson and Dr. Christopher Roy
  • Virginia Polytechnic Institute and State University
  • Holden Auditorium (Room 112)
  • 4:00 p.m.

Aug. 24, 2015 – The seminar will provide an update on the state of the department from the AOE Department Head and a review of the guidelines for graduate students from the Graduate Program Director. This first seminar will be used to address current or recent issues related to scholarly ethics and integrity, including examples from the AOE Department and from the larger academic community. Attendance at this seminar is mandatory.

  • Dr. Sameer Mulani
  • University of Alabama
  • 331 Randolph Hall
  • 3:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

July 21, 2015 – To predict the effects of aleotoric uncertainties in the system responses, most of the times, polynomial chaos has been preferred due to its efficiency and accuracy over other methods. Different non-intrusive polynomial chaos methods have been proposed to increase its general applicability compared to intrusive approach. The DARPA, DoD, and other government agencies are more interested in applying uncertainty quantification (UQ) techniques to real-world problems. This has forced us to look for ways to improve the efficiency of these methods by many orders. The double exponential integration (DEI), Richardson extrapolation and decomposition using differentiation have been applied in polynomial chaos and sampling techniques. During the talk, these techniques’ details along with their advantages will be discussed. The DEI has been integrated with sparse grids to improve the efficiency further and this combined technique will be compared with the traditional sparse grid technique (Clenshaw-Curtis). The DEI is applied to singular function’s UQ where traditional methods fail. Finally, a new method, ‘decomposition with differentiation’ will be presented which integrates polynomial chaos with differentiation operation and this technique turns out be highly efficient as compared to other methods.

Biography:

Dr. Sameer B. Mulani graduated from Indian Institute of Technology Bombay (IIT Bombay), Mumbai, India, with Masters in Aerospace Engineering. During his Master’s, he was awarded with DAAD fellowship to carry out Master’s thesis work at the Institut fur Statik und Dynamik der Luft- und Raumfahrtkonstruktionen (ISD), Universitat Stuttgart, Germany. He completed his PhD in July 2006 from Aerospace and Ocean Engineering at Virginia Tech. He was Post-doctoral Associate and Research Scientist till the end of 2013 December in the Department of Aerospace and Ocean Engineering at Virginia Tech and carried research in the area of Multi-Disciplinary Optimization and Uncertainty Quantification. Currently, he is an Assistant Professor in the Department of Aerospace Engineering and Mechanics at the University of Alabama.

  • Dr. Tarun Kant
  • Indian Institute of Technology, Bombay
  • 331 Randolph Hall
  • 3:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

July 7, 2015 – The author will describe the fundamental research that he has been involved with on higher order plate/shell theories. Most modern structures are made of advanced laminated composite and sandwich materials to exploit their high degree of anisotropy and inhomogeneity across the thickness to reduce weight without sacrificing strength, integrity and durability. In addition, to achieve optimum performance they are made of functionally graded materials (FGMs) that have continuously varying volume fractions of constituents to provide the desired functionality. Due to the inhomogeneity in material properties, accurately modeling and designing these structures is very challenging, and has been intensely researched in the last four decades across the world and Professor Kant has made seminal contributions in this area, for which he is renowned internationally. Two dimensional (2D) plate/shell theories are developed to approximate deformation fields in real three dimensional (3D) structures that have one dimension much smaller than the other two dimensions. Thus, some information in lost in this transformation of modeling of 3D structures with 2D approximate plate/shell theories. However, for designing them one needs accurate knowledge of stresses developed in the structure. Professor Kant’s recent efficient and clever technique to accurately recover these stresses (e.g., see “A general partial discretization methodology for interlaminar stress computation in composite laminates, Computer Modeling in Engineering & Science 17(2), 135-161, 2007”) by the marriage of finite element (FE) and numerical integration (NI) techniques is considered to be first of its kind in the realm of elasto-statics.

Biography:

Born on 1 July 1946 at Ballia in Uttar Pradesh, he received his BSc degree from the University of Allahabad in 1962, his BTech (Hons) in civil engineering from the Indian Institute of Technology Bombay (IIT Bombay) in 1967 and MTech in civil engineering with specialization in structural engineering from the Indian Institute of Technology Kanpur (IIT Kanpur) in 1969. He spent about one and a half year in a consulting engineering firm in Mumbai before joining IIT Bombay as a Lecturer. He earned his PhD degree while working as a Lecturer from IIT Bombay in 1977. He was selected as an Assistant Professor in 1978 and a Professor in 1986. He has held the positions of the Department Head (2000-2002), the Dean (Planning) of the Institute (2001-2003), the Chairman of the prestigious Joint Entrance Examination (JEE-1998) and the Chairman of the Central Library (1995-1999) with great distinction. The Institute appointed him as an Institute Chair Professor from 31st December 2009.

Professor Kant was elected a Fellow of the Indian National Academy of Engineering (INAE) in 1999, a Fellow of the Indian Academy of Sciences (IASc) in 2004, a Fellow of the Indian National Science Academy (INSA) in 2007 and a Fellow of the National Academy of Sciences, India (NASI) in 2011. He is the first and only civil engineer in the country to get elected to all the four national academies. He was a visiting professor at University of Wales, Swansea (1979-’82), University of Cambridge (1993) and University of California, Los Angeles (2005). He is a recipient of the Burmah-Shell Best Paper Prize. He was awarded the 1979 Jawaharlal Nehru Memorial Trust (U.K) Scholarship and the 1992-’93 European Commission (EC) Senior Faculty Exchange Fellowship, both by the Government of India. IIT-Bombay, on 13 March 2007, conferred the 2006 Professor H.H. Mathur Award for Excellence in Research in Applied Sciences in recognition of his outstanding work in the area of Mechanics of Composite Materials and Structures. He also received the 2009 Khosla National Award for his life time achievement in the field of engineering. He is also a recipient of the 2010 IIT Bombay Research Paper Award. IIT Bombay, on 4th April 2012, conferred on him the 2011 Life Time Achievement Award. ICCS17 (17th International Conference on Composite Structures, Porto, Portugal, 17-21 June 2013) honoured him by calling him a legend and recognized him as a pioneer in initiating a new direction in mechanics of composites. Very recently he received the APACM Senior Scientist Award of the Asia Pacific Association of Computational Mechanics (APACM) on 12 December 2013 during APCOM2013 in Singapore and the ICCES (International Conference on Computational and Experimental Engineering and Sciences) Lifetime Achievement Medal in Reno, Nevada, USA on 20-24 July 2015 for making seminal contributions to composite materials and to the education of generations of students in India.

He has published more than 147 research papers in refereed journals, 6 chapters in edited books, about 163 papers in conference proceedings, edited 4 books and currently serves on the editorial boards of 5 international journals. He has supervised 25 PhD theses and over 76 MTech dissertations. He has Research & Citation Standing in terms of h-index of 28 on Web of Science (35 on GoogleScholar). His current citations are over 2000 on Web of Science (over 4000 on GoogleScholar).

  • Dr. William Oberkampf
  • Consulting Engineer
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Hosts: Dr. Christopher Roy and Dr. Pradeep Raj

May 4, 2015 – Simulation is becoming the primary tool in predicting the performance, reliability, and safety of engineered systems. To many managers, decision makers and policy makers not trained in modeling and simulation, these simulations can appear most convincing with their captivating video graphics. Terminology such as “virtual prototyping,” “virtual testing,” and “full physics simulation” are extremely appealing when budgets and schedules are highly constrained, or when competitive pressures force project managers to move forward with little or no testing of subsystems or systems. Many contend that higher fidelity physics modeling, combined with faster computers, is the path forward for improved decision making based on simulation. I argue that improved predictive uncertainty is the most constructive path forward. Predictive uncertainty estimation is the emerging field attempting to capture all aspects of uncertainty in the simulation of a system. The tradition in uncertainty estimation is to focus on propagation of input uncertainties through a mathematical model to obtain uncertainty in the system response quantities of interest. In contrast, predictive uncertainty attempts to capture this uncertainty as well as all potential sources of uncertainty. These include numerical solution error, model form uncertainty, and uncertainty in the environments and scenarios to which the system could be exposed, either intentionally or unintentionally. This talk will briefly review the traditional uncertainty quantification approaches that have been developed in fields such as nuclear power reactor safety. An important distinction is made between uncertainties that are random or stochastic (aleatory uncertainties) and those that are due to lack of knowledge (epistemic uncertainties). It is argued that imprecise probability approaches are the most appropriate method to represent the total predictive uncertainty in simulation-based decision-making.

Biography:

Dr. William L. Oberkampf received his PhD in 1970. He has 44 years of experience in research and development in computational mechanics. He was on the faculty at the University of Texas at Austin until 1979. From 1979 until 2007 he worked at Sandia National Laboratories in both staff and management positions. During his career he has been deeply involved in computational and experimental research and development in fluid dynamics and heat transfer. During the last 20 years he has been focused on verification, validation, uncertainty quantification, and risk analyses of high consequence systems. He is a Fellow of the American Institute of Aeronautics and Astronautics. He has over 178 journal articles, book chapters, conference papers, and reports, and has taught 44 short courses in the field of VVUQ. He and Prof. Chris Roy co-authored the book "Verification and Validation in Scientific Computing" published by Cambridge University Press.

  • Mr. Eric Gustafson
  • Structural Design and Analysis, Inc.
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Robert Canfield

April 27, 2015 – The heatshield carrier is a vital component of the Orion Multipurpose Crew Vehicle (MPCV) and is instrumental in protecting both the vehicle and its crew. The heatshield carrier must provide a sturdy foundation for the outer ablative layer, resist the effects of atmospheric reentry, and bear the impact of a water landing without becoming an excessive mass burden on the Orion spacecraft. Because of this, Structures.Aero worked with the NASA National Engineering Safety Center (NESC) to design an alternate heat shield with the goal of a 25% reduction in system mass over the baseline Titanium stringer-composite skin design. This would require an innovative strategy to develop a design and analysis process that utilized multiple simulation codes to deliver a final lightweight design.

Traditional modeling practices use “loads” and “stress” finite element models (FEMs), with the former suitable for initial sizing and the latter serving to verify prior conclusions about model behavior. Analogous to the standard two-model system, two independent FEM types were developed and maintained for this project. The first FEM type used in preliminary sizing and trade studies utilized “smeared” properties that simulated the strengths and stiffnesses of open panels supported around their perimeter. These models were simpler, faster to iterate, and permitted the generation of a multitude of trade concepts in Hypersizer that could save mass. The second FEM type was a detailed representation of geometric features of the chosen concept. Referred to as the “explicit” model, it enabled final detailed analysis of a chosen concept’s structural features.

Trades were evaluated and a Titanium orthogrid was ultimately down-selected. A practical orthogrid sizing process was developed that first used linear analysis on the smeared FEM for the rough design, then allowed for localized yielding through nonlinear assessments of stiffness, strength, and stability in the explicit FEM. Iterating the design with LS-DYNA took advantage of the inherent damage tolerance of the orthogrid concept by permitting loads to redistribute in a non-detrimental manner. This approach effectively used material plasticity to save mass, but was initially challenging to incorporate in the design cycle due to the arduous nature of verifying congruency between translated models.

The design and analysis approach was validated by drop-testing a 20” diameter subscale titanium orthogrid test article. This test article was first designed and modeled with the developed approach for purposes of validation. Test predictions were also part of the verification process to corroborate the results of Nastran’s implicit nonlinear transient solutions and explicit solutions from LS-DYNA. Dynamic drop tests were completed and compared to the converged predictions. The methods were validated by the dynamic tests. A lighter-mass structural concept was uncovered by a trade analysis which led to a new set of design and analysis procedures undertaken on the down-selected design. The new process for design and analysis of the orthogrid structure smoothed the workflow between numerous analysis codes, and the streamlined design cycle netted a nearly 50% mass reduction on the baseline design. This far exceeded the original goals of the project by delivering a significant potential mass savings to the Orion program.

Biography:

Mr. Gustafson is an aerospace structural engineer for Structural Design and Analysis, Inc. He holds both B.S. and M.S. degrees in mechanical engineering from Virginia Tech. He has accrued years of experience on projects working the primary structure of various small, medium, and large UAVs in addition to the current NASA Orion spacecraft program. Eric's past experience has spanned design, analysis, and manufacturing. His structural focus has been in finite element analysis and applications of composites in primary structure. Eric is also the author of the new book, "Learning Femap".

  • Dr. Martin Mlynczak
  • NASA Langley Research Center
  • 135 Goodwin Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Joseph Schetz

April 23, 2015 – Atmospheric science is relentlessly driven by the need for observations. Weather forecasts rely on satellite and ground based observations to provide the initial conditions which are integrated forward in time to produce the forecast. Chemists rely on measurements of ozone and other minor species to assess the atmosphere’s ability to shield Earth’s surface and inhabitants from harmful ultraviolet radiation. Climate scientists use measurements of incoming solar radiation and the outgoing infrared radiation from the Earth to assess the energy balance of the planet. Aeronomers and space scientists use observations of the high atmosphere to understand the interaction of the Sun and the atmosphere extending hundreds of km above Earth’s surface. Many of these observations are provided by measuring components of the infrared emission spectrum of the Earth and its atmosphere. In this talk I will review some of the basic principles of infrared radiative transfer in Earth’s atmosphere and show how measurement of the infrared spectrum can be used to derive temperature, density, minor species (e.g., ozone) abundances, as well as energetic constraints on the atmospheric climate. I will give special emphasis on results in Earth’s mesosphere and thermosphere obtained from the NASA TIMED satellite and its infrared sensor, the SABER instrument. We will show how the variability of the Sun (both the ultraviolet photons emitted from the Sun and the solar wind) can drive large changes in the upper atmosphere on timescales ranging from days to decades. I will conclude by discussing long-term changes in the upper atmosphere associated with increasing carbon dioxide, and the effects this may have on atmospheric density and the lifetime of orbiting objects.

  • Dr. Richard Wahls
  • National Aeronautics and Space Administration (NASA)
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Hosts: Dr. Rakesh Kapania and Dr. Joseph Schetz

April 20, 2015 – NASA Aeronautics is addressing the challenge of enabling the sustained growth of the air transportation system through the research and development of systems and technologies for future aircraft and airspace operations. Current research programs are addressing energy and environmental issues, as well as expanded mobility/capacity options and enhanced aviation safety. This presentation highlights select subsonic transport aircraft concepts and enabling technologies that address solutions for the revolutionary energy efficiency and dramatic reductions in harmful emissions and perceived community noise that will be required in the coming decades.

Biography:

Dr. Wahls is the senior technical and strategy advisor to the Director of NASA Aeronautics’ Advanced Air Vehicles Program. He leads, manages, and technically contributes to multidisciplinary fundamental research advancing the energy efficiency and environmental compatibility of advanced transport aircraft, and to applied research and development of tools, technologies, and concepts for all vehicle classes from subsonic through supersonic speeds.

Dr. Wahls has experience in computational and experimental aerodynamics, and is the author or co-author of 73 technical publications. His personal research has emphasized high Reynolds number aerodynamics and scale effects utilizing the unique capabilities of the US National Transonic Facility, and the study of innovative aerodynamic technologies and aircraft configurations.

Dr. Wahls is a Fellow of the America Institute of Aeronautics and Astronautics, where he is currently a Deputy Director of the Aircraft & Atmospheric Systems Group, a member of the Applied Aerodynamics Technical Committee and Green Engineering Program Committee, and a charter member of the AIAA Drag Prediction Workshop Organizing Committee. Dr. Wahls received his B.S. (1984), M.S. (1986), and Ph.D. (1989) degrees from North Carolina State University in aerospace engineering.

  • Dr. Matthew Fotia
  • Air Force Research Laboratory
  • 155 Goodwin Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Kevin Wang

April 17, 2015 – Alternative pressure gain combustion thermodynamic cycles are being investigated in the effort to provide a step function increase in the performance available to aerospace propulsion systems. Detonation based cycles are one such technology that holds this promise. Current areas of research include the development of air-breathing, rotating detonation engine devices that allow for the continuous combustion of reactants through a detonation wave. Both high-speed and gas turbine based applications are currently being examined.

Rotating detonation engines are closely coupled systems in which the detonating combustion process directly feeds back into the internal shock-wave mechanics of the device, influencing both the operability and performance attainable from these systems. The basic wave mechanics will be presented, as well as some of the current efforts to address the thrust production, the harsh thermal environment and the influence of propellant mixing on ignition.

Biography:

Dr. Fotia is currently a Research Engineer working as a contractor to the combustion branch of the Air Force Research Laboratory (AFRL/RQ). His research has been focused on the design and development of rotation detonation engines for aerospace applications, including the experimental performance, device nozzling and acoustic coupling with in these systems. Previous to his current position, Dr. Fotia has been a National Research Council research associate at AFRL and a research assistant with the University of Michigan, where he conducted ram/scram transition and shock-train/combustion coupling experiments, as well as design work on highly turbulent flame experiments.

  • Dr. Matthew Hutchison
  • Aurora Flight Sciences Corporation
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

April 13, 2015 – The seminar will provide a survey of a number of development programs with which Dr. Hutchison has been involved over the course of 22 years in the unmanned-aircraft sector of the aerospace industry. The talk will touch on key technical elements of the programs presented and attempt to highlight connections to areas of study within the AOE Department today.

Biography:

Dr. Matthew (Matt) Hutchison is currently Vice President of Engineering at Aurora Flight Sciences Corporation where he is responsible for engineering organizational leadership and technical direction across the company’s multiple business areas.

Dr. Hutchison holds a Bachelor’s degree in Mechanical Engineering (1986) and a Doctorate in Aerospace Engineering (1993), both from Virginia Tech.

His professional career began as a field engineer with General Electric in the power-generation industry between his undergraduate and graduate studies. After graduate school, he started with Aurora as the leader of the company’s aero / performance team. Subsequent management roles have included program chief engineer, program manager and Vice President of Tactical Systems. In 2001, he was a key member of the team that spun off Athena Technologies, Incorporated to focus on the development of highly integrated navigation and controls systems for the unmanned aircraft market. At Athena, he held the role of Vice President, Operations. In 2008, Athena was acquired by Rockwell Collins and became Rockwell Collins Control Technologies. At Rockwell Collins, he held several management roles, including leadership of the UAS and Control Technologies business and site leadership of the Warrenton, VA operations. In 2014, he returned to Aurora in his current position.

Dr. Hutchison has over 20 years of experience in the aerospace industry with a particular focus on the design, development, testing and operations of unmanned aircraft. In arguably the most dynamic sector of the industry over the last 20 years, he has led initial system conceptual definition, detailed system design, aero-structure design and manufacture, navigation and control system development and application, flight testing, deployment and support of field operations.

  • Dr. Farhad Aghili
  • Canadian Space Agency
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Joseph Schetz

April 6, 2015 – The history of in-orbit robotics began three decades ago by deployment of the Shuttle Remote Manipulator System (SRMS), also known as Canadarm, which has played a key role throughout the Space Shuttle Program and then later in the International Space Station (ISS) Program. The Space Station robotic system was complemented by deployment of a dual arm manipulator called Dextre capable of completing human--‐scale delicate servicing tasks. These robotic capabilities have been used to perform assembly and maintenance of ISS, inspection and support EVA operations, and capture/docking of cooperative spacecraft and ISS visiting vehicles. Since then, the paradigm of in-orbit servicing using a space manipulator has attracted many researchers, motivated by several national and international missions in the horizon for repairing, rescuing, and refueling failed satellites as well as for removing large orbital debris. The speaker starts off by reviewing the robotic component of the Space Station and some if its enabling technologies developed through several in-house R&D projects. In particular, the research pertaining to zero- g dynamic emulation of spacecraft and space manipulator and an innovative conceptual design of reconfigurable manipulators, which outlined the Next Generation Canadarm (NGC) project, will be presented. The remainder of the talk will be devoted to present multi-disciplinary research in the area of vision-guided robotics for satellite servicing or orbital debris removal missions. Motion and parameter estimation of uncooperative satellites using laser vision data and optimal guidance for autonomous rendezvous and capture will be discussed.

Biography:

Following completing his Ph.D. program at McGill University in 1998, Dr. Aghili joined the Canadian Space Agency (CSA) where has been Mission Operation Engineer, Systems Engineer, and Federal Research Scientist at the Canadian Space Agency (CSA), where he contributed to the Canadian Space Exploration and the International Space Station (ISS) programs in various capacities. Dr. Aghili has established a robust research and development program by applying his expertise in dynamics, controls, and robotics leading to many technology transfers to industry. His research resulted in over 130 scientific papers, 3 book chapters, 10 patents in US and Canada, 6 trade secretes, and several technology transfers to industry. He also chaired and been otherwise involved in several international conferences and professional activities as well as being the recipient of the best paper award and invited keynote speaker in international conferences. Dr. Aghili is Technical Editor of the IEEE/ASME Transactions on Mechatronics (TMech) and the Chair of IEEE Montreal Robotics & Automation Chapter.

  • Dr. Eric Nielsen
  • NASA Langley
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Seongim Choi

March 31, 2015 – An overview of research based on the NASA Langley CFD solver FUN3D will be presented. Algorithmic development efforts towards adjoint-based error estimation, mesh adaptation, and design optimization will be shown for both steady and unsteady flows, including recent results for chaotic behavior typically observed in large scale eddy-resolving simulations. Analysis and design methodologies will also be demonstrated for a broad range of aerodynamic and multidisciplinary applications including flow control, fluid-structure interaction problems, rotorcraft, launch and re-entry vehicles, rotorcraft simulations, and sonic boom prediction and mitigation. Related topics such as software development practices and high performance computing strategies will also be discussed.

Biography:

Dr. Eric Nielsen is a Senior Research Scientist with the Computational AeroSciences Branch at NASA Langley Research Center in Hampton, Virginia. He received BS and PhD degrees in Aerospace Engineering from Virginia Tech and has worked at Langley for the past 22 years. Dr. Nielsen specializes in the development of computational aerodynamics software for the world's most powerful computer systems. The software has been distributed to thousands of organizations around the country, and supports major national research and engineering efforts at NASA, in industry,
academia, the Department of Defense, and other government agencies. He has published extensively on the subject and has given presentations around the world on his work. Dr. Nielsen has received NASA's Exceptional Achievement Medal and was recently awarded Langley's 2014 HJE Reid Award for best research publication.

  • Dr. Mark Psiaki
  • Cornell University
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Joseph Schetz

March 30, 2015 – Solutions of model-based estimation problems can be used to enhance scientific and engineering endeavors that range from spacecraft attitude and orbit determination to remote sensing of the Earth's atmosphere. The common threads in these problems are the existence of hidden internal states, the availability of sensor data, and an ability to model the dependence of the data on the states. An estimation practitioner must invert the forward model in order to infer the states from the data. One must also estimate the potential inaccuracies caused by model and measurement uncertainties. Standard solutions include a batch filter for static problems, Kalman filters for systems with dynamically varying states, and Ensemble Kalman filters (EnKF) for systems with enormous numbers of states. A good solution involves the development of an accurate system model and the use of an appropriate inversion algorithm. An important aspect is the art of appropriately simplifying and tuning models when needed.

Recent theoretical contributions to estimation include a new Gaussian mixture filter and a new EnKF. The new Gaussian mixture filter provides a powerful tool for solving difficult nonlinear estimation problems, problems that cannot be solved by the “usual suspects”: Extended Kalman filters (EKFs), Unscented Kalman filters (UKFs), or Particle Filters. The contribution to Gaussian mixture filtering is a new mixture re-sampling algorithm that limits mixand covariance, thereby enabling the use of EKF or UKF calculations for the individual mixands within a static multiple model filtering framework. Comparisons of this algorithm with other nonlinear filters are presented for the 7-state Blind Tricyclist benchmark problem. Current efforts to apply this filter to Space Situational Awareness problems are also discussed.

The new EnKF provides a tool for solving estimation problems with very large numbers of states, on the order of 105-108. Such problems are too large to store and update the filter’s full estimation error covariance matrix. A traditional EnKF stores and updates only a low-rank approximation of the covariance square-root. The new filter works instead with a low-rank approximation of an increment to the filter’s square-root information matrix. Its execution speed is on the order of traditional EnKFs, but it removes the two traditional ad hoc fixes: localization of measurements during the measurement update and covariance inflation as a substitute for process noise during the dynamic propagation. Instead, it uses an assumed a priori covariance, one that would exist if there had never been any measurement updates. A diagonal approximation or some other sparse approximation of this a priori covariance can be used, thereby avoiding large computation costs associated with its inversion. Initial comparisons on a simulated “toy” problem will be used to demonstrate the benefits of this new EnKF when using measurements that are like GPS radio-occultations applied to an upper atmosphere model.

Two recent applications of estimation theory will also be discussed, GPS spoofing detection and remote sensing of the local ionosphere. One spoofing detection method exploits direction-of-arrival information as deduced from a small 2-antenna array. It has been tested against live-signal spoofing attacks during a cruise around Italy in late June 2014.

The remote sensing work fuses GPS TEC data and ionosonde data in order to deduce a local ionosphere model above the HAARP array on Gakona, AK. This effort constitutes the initial step of a project that aims to develop global real-time corrections to the International Reference Ionosphere model.

  • Dr. Stelios Kyriakides
  • The University of Texas at Austin
  • 3081 Derring Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Kevin Wang

March 27, 2015 – The design of pipelines installed in deep waters is governed by buckling and collapse considerations. An equally important consideration is safeguarding the line against the potential occurrence of a propagating buckle. A buckle that propagates can be initiated from the collapse of a locally damaged section of the pipeline. Once initiated, the buckle propagates at high velocity, and has the potential to quickly destroy the whole line. The lowest pressure at which such a buckle propagates is the propagation pressure, a characteristic pressure of the pipe. The propagation pressure is typically only 15% to 20% of the collapse pressure of an intact pipe, and so designing the line based on the propagation pressure is impractical. The preferred alternative is to base the design on the collapse pressure, and to install buckle arrestors at regular intervals along the pipeline. In the event a propagating buckle is initiated, the arrestors limit the damage to the length of pipe separating the arrestors on either side of the initiation site (typically several hundred meters). Buckle arrestors are devices which locally increase the circumferential bending rigidity of the pipe, and thus provide an obstacle in the path of a propagating buckle. The arrestors are typically thick-walled rings which are slipped over or welded into the pipeline. The lecture will use results from experiments and analysis to review fundamental and practical aspects of the initiation of a propagating buckle, its quasi-static and dynamic propagation, and its arrest, as they influence the design of modern offshore pipelines.

Biography:

Stelios Kyriakides obtained his PhD in aeronautics from the California Institute of Technology in 1980. He joined the Department of Aerospace Engineering and Engineering Mechanics of The University of Texas at Austin in the same year, where he has served as professor since 1989. Currently he is Director of the Center for Research in Mechanics of Solids, Structures and Materials and holder of the Cockrell Family Chair in Engineering No. 10.

Professor Kyriakides’ research focuses on instabilities that limit the extent to which solids, structures and materials can be loaded or deformed. He has published more than 190 technical articles, one book and one monograph. He served as chair of the Executive Committee of the Applied Mechanics Division-ASME, as President of the American Academy of Mechanics (AAM), as chair of the US National Committee of Theoretical and Applied Mechanics, and is Editor of the International Journal of Solids and Structures. His recognitions include the 2009 Warner T. Koiter Medal from the American Society of Mechanical Engineers (ASME), Member of the US National Academy of Engineering, and Fellow of ASME and AAM.

More information about the speaker can be found at http://research.ae.utexas.edu/mssm/faculty/stelios-kyriakides.php.

  • Dr. Sheryl Grace
  • Boston University
  • 310 Kelly Hall
  • 1:00 p.m.
  • Faculty Host: Dr. William Devenport

March 24, 2015 – On approach when a commercial aircraft’s engines are throttled down, the fan stage becomes the main engine noise source. The noise exists mainly due to the interaction of the fan rotor wake with the fan exit guide vanes (FEGVs). Both tonal and broadband noise is produced. We have developed a computational hybrid method that can be used during the design phase to predict the broadband interaction noise. A low-order cascade response solution forms the backbone of the RSI (rotor-stator interaction) method that will be discussed. Input to RSI consists of rotor wake properties currently taken from either experimental data or a Reynolds Averaged Navier Stokes (RANS) flow simulation. The basis for and outcomes of modeling choices made within the RSI framework will be presented. Comparison between measured and predicted noise levels indicates the method can provide the trend prediction necessary for design.

Biography:

Professor Grace’s research interests lie in the fields of unsteady aerodynamics and aeroacoustics. She has twice been invited to lecture at the von Karman Institute for Fluid Dynamics as part of the Aeroacoustics series. She has made contributions to her field through her work on inverse methods for source/disturbance identification and investigations of aperture and cavity flows. In the past she has received funding from both GEAE and Boeing for work related to aircraft and engine noise. Currently, she is funded by the Aeroacoustics Research Consortium to benchmark existing, and develop alternative, methods for utilizing CFD in the prediction of fan noise.

Beyond her research and teaching, Professor Grace is a past faculty advisor for the student chapter of AIAA at Boston University, for which she won the National Faculty Advisor Award. She has worked on numerous outreach activities for K-12. She was instrumental in founding the Women in Science and Engineering Committee at Boston University, was Co-PI on an NSF ADVANCE PAID grant, and continuously works to improve recruitment and retention of women in science and engineering. She also contributes to society at large as exemplified by her recent service to the Massachusetts Department of Environmental Protection and to the Canadian Research Council as a member of expert panels reviewing the health impacts of wind turbines.

Prior to joining BU she earned her PhD in aerospace engineering at The University of Notre Dame, an MS in Applied Mathematics at Oklahoma State University, and a BS in mathematics at the University of Akron.

  • Mr. Geoff Patterson
  • University of Hawaii
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

March 16, 2015 – Temporarily-captured Natural Earth Satellites (NES) are near Earth asteroids that get temporarily caught in orbit around Earth. These objects intuitively make appealing targets for space missions because they are very close to home. In order to determine just how appealing they are, fuel-minimal asteroid rendezvous missions are investigated using a catalogue of over sixteen-thousand simulated NES. The spacecraft is assumed to start at the Earth-Moon L2 Lagrangian point, with specifications comparable to a chemical propulsion system. The Circular Restricted Four Body Problem is used to model the gravitational effects of the Earth, Moon, and Sun. Indirect methods of optimal control based on the Pontryagin Maximum Principle are employed to identify fuel-optimal transfers, and a foliation technique is used to overcome the well-known difficulty of initializing such algorithms. Our methods produce rendezvous missions for a significant percentage of the simulated asteroids, with delta-v values as low as 44 meters per second.

Biography:

Mr. Patterson is completing his doctorate in mathematics at the University of Hawaii at Manoa under the mentorship of Dr. Monique Chyba.

March 9, 2015 – Classes are not in session from March 7th to March 15th in observation of Spring Break.

  • Dr. Alex Main
  • Duke University
  • 135 Goodwin Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Kevin Wang

March 5, 2015 – This talk examines the design and implementation of embedded boundary methods for problems involving multiphysics, specifically those involving fluid-fluid and fluid-structure interactions, with an emphasis on those problems involving complex, highly nonlinear phenomena. A second order accurate embedded boundary method is introduced for fluid-fluid and fluid-structure interaction. The accuracy and stability of these embedded boundary methods are examined, by introducing tools to quantify the stability of embedded boundary methods, and techniques are introduced to stabilize embedded boundary methods as necessary. The methods developed are demonstrated on a variety of fluid-fluid and fluid-structure interaction problems.

Biography:

Dr. Alex Main is a post-doctoral associate at Duke University working with Guglielmo Scovazzi. His interests are in coupled multiphysics problems, embedded (and ghost) boundary methods, high performance/vector computing, and tools for developing massively parallel codes. He graduated in November 2014 with a PhD from Stanford University. His advisor at Stanford was Charbel Farhat, with a thesis titled "Implicit and Higher Order Discretization Methods for Compressible Multi-Phase and Fluid-Structure Interaction Problems".

  • Dr. Seongkyu Lee
  • GE Global Research
  • 3100 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. William Devenport

Feb. 26, 2015 – This seminar presents recent research activities about wind turbine blade aeroacoustics and numerical predictions for acoustic scattering. Wind power capacity has expanded rapidly to 336 GW in June 2014, and wind energy production is around 4% of total worldwide electricity usage, and growing rapidly. As the number of wind turbines increases, they are being located closer to business and residential areas that may have various laws and regulations restricting noise levels. This seminar presents the issues and research opportunities for wind turbine noise. A main aerodynamic noise source of wind turbine blades is the blade trailing edge noise which is generated by scattering by a sharp trailing edge of the pressure fluctuations in the turbulent boundary layer. This seminar presents a design approach to mitigate this noise by modifying the trailing edge geometry to reduce the scattering effect. A new time-domain acoustic scattering solver and analytic formulations of the pressure gradient are presented. In the acoustic scattering solver, equivalent point sources are embedded inside the scattering body, and the strength of the sources is determined by matching the boundary condition on the surface. Acoustic scattering of broadband and impulsive noise is presented. Acoustic scattering of BO105 helicopter noise by a fuselage is also predicted and validated with NASA’s Fast Scattering Code. Finally, future research plans and potential collaborative opportunities are discussed.

Biography:

Dr. Seongkyu Lee is a lead mechanical engineer at Aerodynamics and Acoustics Lab, General Electric (GE) Global Research Center in New York. Dr. Lee joined GE Global Research as mechanical engineer in 2010 after a post-doctoral scholar position at the Pennsylvania State University. Recently, Dr. Lee took a position of Advanced Design Tool program manager at GE Global Research, and he leads the development of new technology tools including CFD and aeroacoustic tools and he manages over 10 million dollar projects. Dr. Lee has extensive research experiences in wind energy, turbomachinery, and rotorcraft aeroacoustics. Dr. Lee’s research experiences at GE include wind turbine blade CFD and aeroacoustics, far-field sound propagation, aircraft engine and propeller noise predictions, and propulsion-airframe aeroacoustic integration. Dr. Lee has led a global team of researchers to design innovative low-noise wind turbine operations. Dr. Lee received his Ph.D. degree in Aerospace Engineering and a minor degree in Acoustics Graduate Program in 2009 from the Pennsylvania State University where he worked on theoretical and computational aeroacoustics for rotorcraft noise, acoustic scattering, and nonlinear sound propagation. He is a member of AIAA and AHS.

  • Dr. Mohammed Afsar
  • Imperial College London
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Feb. 23, 2015 – I show how a fundamental approach to aero-­‐acoustic modeling of flow generated noise and jet surface interaction noise can provide insight into the physics of sound generation as well as providing a viable prediction tool for industrial design. The basic approach involves using Goldstein’s (2003) generalized acoustic analogy equations, which is simply an appropriate re-arrangement of the Navier Stokes equations such that the acoustic field is expressed as integral of the fluctuating Reynolds stress tensor and an adjoint Green’s function propagator. The flow Reynolds number is assumed to be asymptotically large and the acoustic Mach number, unless otherwise stated, is subsonic.

The talk is organized as a historical overview of the results we have obtained in the last decade. Two essential ingredients go into jet noise and jet surface interaction noise models, that is: i). structural modeling of turbulence using its symmetries; and ii). analysis of wave propagation using asymptotic and numerical calculations. For example, Afsar (2010) showed how Professor Geoffrey Lilley’s classical ideas of shear noise and self noise can be obtained much more consistently as the leading order terms in the low frequency asymptotic expansion of propagator tensor in the acoustic spectrum formula. This idea was later adapted to consider more a realistic turbulence representation (Afsar et al. 2010, Karabasov, Afsar et al. 2010 & Afsar 2012) and expanded to take into account non-­‐parallel mean flow effects (Goldstein, Sescu & Afsar 2012). When considering the effect of heating, we showed that the enthalpy flux-­‐momentum flux coupling term introduces cancellation in the acoustic spectrum at low frequencies due to the odd power in the inverse Doppler factor (Afsar, Goldstein & Fagan 2011). Hence this mechanism could serve as a purely fluid mechanical means of jet noise control.

My work on jet surface interaction has focused on modeling low frequency trailing edge noise. Experimental data indicating low frequency trailing edge noise could be much as 10 dB greater than the jet noise itself, motivated this study.

The model we developed (Goldstein, Afsar & Leib 2013a & b; Afsar & Leib 2015) showed, among other things, that exact integral solutions of the Rapid Distortion Theory (RDT) equations can be expressed in terms of two integral curves of the Euler equations (i.e. functions of arbitrary convected scalar quantities) and the Rayleigh equation Green’s function. The complexity in this problem, however, lies in the fact that only certain spatial locations of the space-time Fourier transform of the transverse momentum field can be specified as an upstream input to the model. Moreover, a physically realizable upstream turbulence spectrum must include a finite de-correlation region in the transverse velocity correlation function. Our latest results show that an increase in “size” of this de-correlation region increases the low frequency algebraic decay of the acoustic spectrum with angular frequency. We conclude by discussing the implication this result has for trailing edge noise control.

Biography:

M.Z. Afsar began his undergraduate studies at the University of Bristol, UK, in Aeronautical Engineering in October 1999. His research career began in the summer of 2002 when, still an undergraduate, he received a Research Assistantship from the Department of Applied Physics at Yale University working under Professor Marshall Long. He worked there as an experimentalist doing laser diagnostics for a laminar flame. He graduated from Bristol in summer of 2003 with a very high First Class Honors degree for which he received the Royal Aeronautical Society Award.

His interest in Aero-acoustics was sparked by lectures of the late Professor Martin Lowson at Bristol University. In January 2004, he began his doctoral work at the University of Cambridge in jet noise modeling under the supervision of Professor Dame Ann Dowling. He completed his Ph.D. in 2008 and in the autumn of that year he received the David Crighton Fellowship from the DAMTP, Cambridge, which he used to work with Dr. Marvin E. Goldstein at the NASA Glenn Research Center. In the spring of 2009 he was a Teaching Assistant/Grader at Robinson College Cambridge. He returned to NASA Glenn in the summer of 2009 as a Short-­‐term Research Scholar funded by Stanford University’s Center for Turbulence Research. Later that year, he was a visiting faculty member at the Department of Mathematics at Kashmir University in Srinagar, India. Between February 2010 and May 2013 he was a NASA Post-­‐doctoral Program (NPP) Fellow working with Drs. M.E. Goldstein, S.J. Leib and J. E. Bridges. In July 2013, he took up the Chapman Fellowship and Laminar Flow Control Research Associateship at the Department of Mathematics at Imperial College London.

  • Dr. W. Nathan Alexander
  • Virginia Polytechnic Institute and State University
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Host: Dr. Michael Philen

Feb. 16, 2015 – The correlated response of rotor blades to ingested turbulence has been shown to generate broadband noise around the blade passage frequency and its harmonics. This noise is produced by the time-delay correlation of the unsteady lift response of each blade which in turn exerts an unsteady force on the surrounding acoustic medium. At zero-thrust conditions, convected turbulent structures pass through the disk plane with little distortion and noise can be predicted with reasonable accuracy knowing the inflow turbulence correlation function. When thrusting, the approach flow turbulence distorts as it is accelerated and, at high thrust, is stretched into long, thin filaments. In this case, the broadband response narrows and can even appear tonal. Accurate representation of the turbulence distortion is vital to predicting the broadband rotor noise, but this is not trivial, especially for complex flows which are inhomogeneous and anisotropic. This presentation details an experimental study in which a 457 mm diameter rotor was immersed in a thick turbulent boundary layer developed on the wall of the Virginia Tech Stability Wind Tunnel. Effects of turbulence distortion were observed through analysis of the noise and unsteady upwash. The influence of rotor yaw was also investigated.

Biography:

Dr. W. Nathan Alexander received his PhD from Virginia Tech in 2011. He is currently a Research Assistant Professor at Virginia Tech studying aero/hydroacoustic noise sources and is a member of the Center for Renewable Energy and Aerodynamic Testing. His past research has focused on the noise produced by rotating machinery, airfoils, and rough surfaces as well as aeroacoustic measurement techniques.

  • Dr. Pieter Buning
  • NASA Langley
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Hosts: Dr. Christopher Roy

Feb. 9, 2015 – This talk will describe the application of the NASA OVERFLOW overset grid computational fluid dynamics (CFD) flow solver to several flow simulation problems associated with the Mars Science Laboratory (MSL). These problems are associated with the Mars atmosphere entry, and with the descent and landing phase, where the descent stage slows down, hovers, and lowers the rover to the ground. In each of these cases, successes and difficulties with the computational approach will be highlighted.

Biography:

Dr. Pieter Buning received BS degrees in Aerospace Engineering and Computer Engineering from the University of Michigan, and MS and PhD degrees in Aeronautics and Astronautics from Stanford University. He joined NASA Ames Research Center in 1979, studying numerical methods, computational efficiency and scientific visualization, authoring the PLOT3D visualization code for CFD.

After spending a year at Boeing, Pieter returned to Ames in 1989 to work on development of overset grid methods, with application to the Space Shuttle launch vehicle. This work, in collaboration with team members at Ames Research Center and Johnson Space Center, led to development of the OVERFLOW CFD code and various grid generation tools for complex configurations. Starting in 1992, these tools were further refined on subsonic commercial transport configurations.

Pieter transferred to NASA Langley in 1996, where he continued to work on CFD tool development and applications, including stage separation, capsule aerodynamics, and Mars entry, descent and landing. He is currently in the Computational AeroSciences Branch, where his research is focused on improving the accuracy of CFD simulation of rotorcraft flows.

  • Mr. Kyle Knight
  • Corvid Technologies
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Hosts: Dr. Rakesh Kapania and Dr. Joseph Schetz

Feb. 2, 2015 – Motorsport teams from F1 to NASCAR increasingly rely on aerodynamics to gain a competitive advantage on the race track. Corvid Technologies employs RavenCFD and onsite analysis to help motorsports teams improve vehicle aerodynamics and win on race day. The lessons learned on track are also applied to production cars, which require drag-reducing components aerodynamic components to decrease fuel consumption. This presentation will review the specialized capabilities of RavenCFD, the common methods for implementing vehicle design changes, and a case study of drag reduction on a low-drag production vehicle, the Aptera. This case study will show the methods used to highlight drag sensitivities and make modifications in a rapid turnaround time.

Biography:

Kyle Knight lives in Charlotte and is currently the Hendrick Motorsports Team Lead at Corvid Technologies. The position requires on site involvement with the four Hendrick teams. The position includes flow analysis to identify design sensitivities, adjusting components, running design iterations in CFD, and finally wind tunnel testing of the design changes. The ultimate goal is to increase vehicle performance on track (aka WIN!).

Mr. Knight is a graduate of Virginia Tech (Aerospace Engineering, B.S. 2009, M.S. 2011)

  • Dr. Bassam Bamieh
  • University of California, Santa Barbara
  • Holden Auditorium (Room 112)
  • 4:00 p.m.
  • Faculty Hosts: Dr. Mazen Farhood

Jan. 26, 2015 – The question of how difficult or easy it is to control a certain network of interconnected dynamical agents is fundamental to understanding engineered or naturally occurring networks, such as vehicular formations or power grids amongst many others. I will argue that standard notions of stability as a binary property (i.e. a system is either stable or not), or convergence rates, may fail to predict the behavior of large networks. This motivates a notion of network controllability based on the best-achievable-performance in optimal control problems with structural constraints. While such problems are known to be generally intractable, I will show certain examples from vehicular platoons and power grids where informative and simple answers are possible in the asymptotic limit of large system size. This analysis gives asymptotic bounds on network performance and shows its dependence on both the complexity of individual node dynamics, as well as network connectivity. Connections between this analysis and the statistical mechanics of harmonic solids, resistive lattices and random walks will be outlined.

Biography:

Bassam Bamieh is Professor of Mechanical Engineering at the University of California at Santa Barbara. His research interests are in the fundamentals of Control and Dynamical Systems such as Robust, Optimal and Distributed Control, as well as the applications of systems and feedback techniques in several physical and engineering systems including shear flow transition and turbulence, and the use of feedback in thermoacoustic energy conversion devices. He is a past recipient of the National Science Foundation CAREER award, the AACC Hugo Schuck Best Paper Award, and the IEEE Control Systems Society G. S. Axelby Outstanding Paper Award (twice). He was elected a Distinguished Lecturer of the IEEE Control Systems Society (2005), a Fellow of the International Federation of Automatic Control (IFAC), and a Fellow of the IEEE.

  • Dr. Fayette Collier
  • National Aeronautics and Space Administration
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Seongim Choi

Dec. 8, 2014 – Created in 2009 as part of NASA's Aeronautics Research Mission Directorate's Integrated Systems Research Program, the Environmentally Responsible Aviation (ERA) Project establishes the feasibility, benefits and technical risk of advanced commercial transport vehicle concepts and enabling technologies to reduce aviation’s impact on the environment.

Current-generation aircraft already benefit from the NASA investments in aeronautical research that have improved fuel efficiencies, lowered noise levels and reduced harmful emissions. Although substantial progress has been made, much more can be achieved to improve future performance of the subsonic commercial transport sector.

Forecasts call for the nation's air transportation system to expand significantly within the next two decades. Such an expansion could bring adverse environmental impacts. To neutralize or reduce these impacts is the goal of the ERA Project and its focused research.

The project is organized to:

  • Mature promising technology and advanced commercial transport configurations that meet mid-term goals for community noise, fuel burn and nitrogen oxides (NOx) emissions as described in the National Aeronautics Research and Development Plan and;
  • Determine the potential impact of these advanced commercial transport designs and technologies if successfully implemented into the air transportation system.

To enable improved environmental performance of advanced commercial transport configurations that might enter service by 2025, the ERA Project is researching technologies while addressing operational hurdles that will simultaneously:

  • Reduce aircraft drag by 8%
  • Reduce aircraft weight by 10%
  • Reduce engine specific fuel consumption by 15%
  • Reduce oxides of nitrogen emissions of the engine by 75%
  • Reduce aircraft noise by 1/8 compared with current standards

Most of the research is broadly applicable to many seat classes in the commercial fleet, and if adopted by the aircraft and engine companies, the technology suite will provide broad based benefits by reducing community noise around airports and reducing the carbon footprint of aviation. Local air quality will also be improved due to reduced LTO NOx emissions, even in the face of increase numbers of operations at most airports.

The speaker will describe the status of the eight technology demonstrators selected for the second phase of ERA and will describe the projected benefit at the fleet level if the technologies are incorporated into future commercial transport aircraft to be used by the flying public by 2025 and beyond.

Biography:

Dr. Fayette Collier is currently the Project Manager of the Environmentally Responsible Aviation Project within NASA’s Integrated System Research Program.

In this capacity, Dr. Collier directs the planning and execution of NASA’s integrated system research project focused on the subsonic transport sector, working in partnership with Industry, FAA, AFRL and other government agencies. The technology development project is focused on research, development and integration of engine and airframe technologies that will enable dramatic improvements in noise, emissions, and performance characteristics of future subsonic aircraft operating in the air transportation system. ERA is currently well into Phase II, where 8 Integrated Technology Demonstrations are underway. The six-year, $420M project will conclude at the end 2015.

Dr. Collier is a graduate of Virginia Tech (Aerospace Engineering, B.S., 1981, M.S., 1982, Ph.D., 1988) and the Massachusetts Institute of Technology (M.B.A., 1997) where he participated as a NASA Sloan Fellow. He serves on numerous committees for the Agency, including the AIAA Honors and Awards Committee, the AIAA International Program Committee, and the AFRL Fixed Wing Executive Council, and he was a contributor to the development of the National R & D Plan for Aeronautics. Dr. Collier is an Associate Fellow of the AIAA.

  • Dr. Bret Stanford
  • NASA Langley Research Center
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Mayuresh Patil

Dec. 1, 2014 – This presentation will review recent progress in the field of aeroelastic topology optimization. Topology optimization involves a process by which an optimizer makes fundamental decisions regarding the layout of structural reinforcement. Many immediate and interesting application areas can be found for topology optimization of aerospace structures (wings, panels, bodies) for which fluid-structure interactions are a key design feature. Computational solution methods are reviewed, and recent results are presented for a range of vehicle design processes driven by complex aeroelastic physics.

Biography:

Dr. Bret Stanford received his B.S. in mechanical engineering in 2003 and his Ph.D. in aerospace engineering in 2008, both from the University of Florida. Dr. Stanford was a postdoctoral research associate at Wright Patterson AFB, Air Force Research Laboratory, through 2012, and is currently a research aerospace engineer at NASA Langley Research Center, in the Aeroelasticity Branch. He is a patent-holder, and the author or co-author of over 100 publications (over 45 peer-reviewed) covering topics such as aeroelasticity, computational design, model reduction, and uncertainty quantification.

Nov. 24, 2014 –

Classes are not in session from November 22nd to November 30th in observation of Thanksgiving Break.
  • Mr. Artur Wolek
  • Virginia Polytechnic Institute and State University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Nov. 17, 2014 – Underwater gliders are robust and long endurance ocean sampling platforms that are increasingly being deployed in coastal waters. The coastal ocean is a dynamic and uncertain environment with significant currents that can challenge the mobility of these efficient (but slow) gliders.

To address this challenge, a series of planar path planning approaches were developed to improve robustness in currents, energy efficiency, or time of flight for maneuvers on the length scale of a few turn radii of the vehicle. Nonlinear optimal control theory (the Minimum Principle, and its geometric interpretation via the Hodograph) was used to study these problems and to develop path synthesis algorithms.

  • Dr. Eric Stewart
  • Marshall Space Flight Center
  • 221 Randolph Hall
  • 3:00 p.m.
  • Faculty Host: Dr. Mayuresh Patil

Nov. 14, 2014 – Marshall Space Flight Center is leading NASA's effort to develop the Space Launch System (SLS), the launch vehicle that will take humans out of low earth orbit for the first time in since Apollo 17. The loads, dynamics, and strengths branch - of which Dr. Stewart is a part - focuses on the structures and structural dynamics issues that will affect the SLS: on-pad loads, propellant slosh, aeroelasticity, vibroacoustics, fatigue, shell buckling, modal analysis, and in-flight loads analysis. This presentation will touch many of these aspects and will dive deeper into some of the ongoing work being done by Dr. Stewart such as modal identification and modal uncertainty.

Biography:

Dr. Eric Stewart is an AST, Structural Dynamics at Marshall Space Flight Center in Huntsville, AL. His work primarily focuses on advanced structural dynamics and building up in-house analytical tools for analysis of the Space Launch System. Prior to joining NASA in January 2014, he received his Ph.D. in aerospace engineering from Virginia Tech. He also has a B.S. and M.S. in mechanical engineering from the University of Florida.

  • Dr. Samantha Magill
  • Honda Aircraft Company
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Nov. 10, 2014 – Presentation Outline:

  1. "Oh the places you will go" - Sam Magill post Virginia Tech
  2. Honda/Honda Aircraft Company overview & timeline
  3. HA420/HondaJet: General & technical overview
  4. Some short videos within the presentation
  5. Based on audience and purpose, I will discuss the relationship between flight test/engineering/certification, i.e. some real-world R&D scenarios.

Biography:

Dr. Samantha Magill has been with Honda Aircraft Company Inc. since 2010, and has had several roles: Technical Marketing and Sales Engineering; Flight Sciences’ Stability & Control Engineer; and mostly recently she has been tapped to lead a new department, Academic Affairs and Diversity & Inclusion.

Dr. Magill completed her M.S. and Ph.D. in aerospace engineering at Virginia Polytechnic Institute and State University and a B.S. in aerospace engineering at Auburn University. After her academic career, she moved to Southern California to work with AeroVironment, Inc. on Small Unmanned Aerial Vehicles (SUAV). Samantha continued her aviation career in Oberpfaffenhofen, Germany, where she collaborated within the Dornier-Fairchild legacy on a ‘start-up’ designing and marketing a new light jet.

Dr. Magill has published several technical papers as well as spoken on behalf of Honda Aircraft and women in aviation as a guest speaker and panelist. She is very active in the community locally and within the industry. She has the honor to serve on many board of directors, advisory councils and committees, a few are: American Institute of Aeronautics and Astronautics, Rotary Youth Leadership Program; United Way of Greater Greensboro; North Carolina Aerospace Initiative, Piedmont Aero Club; Junior League of Greensboro; and The International Civil Rights Center & Museum.

Dr. Magill resides in downtown Greensboro and enjoys visiting family as well as training and competing in triathlons.

  • Dr. Alireza Esna Ashari
  • Georgia Institute of Technology
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Mazen Farhood

Nov. 3, 2014 – Any practical system is subject to various major changes, as well as the unknown faults, which may change the behavior of the system and may lead to significant performance degradation and serious damages. We need to detect abnormal behaviors of the system before taking further action. Active detection methods use various types of interaction with the system to improve the detection of faults. A test signal, designed to highlight faults and variations, is fed into the system. Unlike passive approaches, active fault detection methods can guarantee the detection of faults under certain conditions. Observer and filters are designed for online monitoring of the system. Once the problem is detected, we can re-adjust the nominal controller for the new situation. This talk will provide an overview of the relevant theory and recent results in this area.

After designing observers and controllers, we implement the methods on digital computers. Computational errors and software bugs, however, may lead to failures. We need to develop reliable software for safety-critical dynamic systems and validate them formally, before practical tests. For that purpose, we translate fault detection and control properties and proofs to machine language. We include the translated properties in software in the form of non-executable annotations. The standard annotations can be validated by automatic software verification tools.

Biography:

Alireza Esna Ashari is a postdoctoral fellow with the School of Aerospace Engineering and College of Computing at Georgia Institute of Technology. He received his Ph.D. from University of Paris-Est, working at Inria (the French National Institute for Research in Computer Science and Control), Paris-Rocquencourt center, France. After his Ph.D., he was a postdoctoral research associate with Inria. His primary research goals are directed towards developing fault detection, estimation and control methods for robust resilient safety-critical systems, as well as large-scale and networked systems.

  • Dr. John Vassberg
  • The Boeing Company
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Oct. 20, 2014 – Aerodynamic characteristics and flight dynamics of boomerangs are investigated. A basic aerodynamic model, developed in the 1960’s, is expanded upon using Blade Element Theory. The new aerodynamic model is coupled with a gyroscope model for rudimentary analyses. Some significant findings are made regarding the radius of a boomerang’s circular flight path, the required inclination angle of its axis-of-rotation, its trim state, as well as its dynamic stability. These discoveries provide a basic understanding of how the interplay between aero-dynamic forces and moments, and gyroscopic precession combine to return the boomerang to its rightful owner by way of a circular flight path.

A traditional V-shaped boomerang design is developed as a case study for further detailed analyses. Unsteady Reynolds-averaged Navier-Stokes solutions provide accurate aerodynamic characteristics of the subject boomerang. The high-fidelity aerodynamic model is coupled with the equations of motion to provide accurate six-degree-of-freedom simulations of boomerang flight dynamics. Boomerang orientation during its flight trajectory is described by the classical Euler angles.

Biography:

Dr. Vassberg is the Lead Aerodynamicist and Engineer of the BCA Design Center in Southern California. Prior to this, he was Chief Aerodynamicist of Boeing’s Research & Technology organization. He is a Boeing Technical Fellow, an AIAA Fellow, and recipient of the AIAA Aerodynamics Award in 2012. Dr. Vassberg actively supports various BCA, BDS and BR&T airplane design programs. He was chief aerodynamicist of the recently-completed Advanced Joint Air Combat System (AJACS), Speed-Agile Configuration Development (SACD) and Over-Wing Nacelle (OWN) programs. [The SACD Program won the 2013 Aviation Week Laureate Award in the Aero and Propulsion category.]

Dr. Vassberg joined Boeing (McDonnell Douglas Corp) in 1982, working in the Aerodynamic Technology Programs group, where he developed or co-developed transonic airfoil technologies such as optimum upper-surface pressure recovery paths, divergent trailing edge and trailing-edge wedge concepts, using computational methods and validating these technology advancements with wind tunnel testing. Since then, Dr. Vassberg has developed, matured, transitioned, and applied numerous computational fluid dynamics (CFD) methods and aerodynamic technologies. In order to accomplish this, he has worked about half of his career in aerodynamic research and technology groups and the other half in aircraft program development organizations. During his 32 year career at Boeing, Dr. Vassberg has continuously engaged and collaborated with NASA Ames and Langley Research Centers, the Air Force Research Laboratory, the Naval Research Laboratory, as well as with various academic institutions. He is considered a world authority in the development and application of CFD and aerodynamic shape optimization for aerodynamic design within an aircraft design environment. Dr. Vassberg is chairman and a charter member of the International AIAA CFD Drag Prediction Workshop (DPW) organizing committee; he is also on the Advisory Board for the AIAA High-Lift Prediction Workshop. Aircraft Programs that he has worked on or supported include: AJACS, C-17, KC-10, MD-11, MD-12, MD-XX, MD-80, MD-90, UHB, B787, B747, B777, B737, B767, B717, BWB, LCF, OAW, and HSCT.

Dr. Vassberg holds over a dozen Patents related to aerodynamic technologies, and has authored over 100 publications. In addition, Dr. Vassberg has introduced and developed new fields of numerical simulation including: in-flight refueling hose-drogue dynamics, towed-decoy dynamics, fast surface-paneling techniques, and globally-elliptic meshing methods.

Dr. Vassberg received his PhD from the University of Southern California in 1992, and his MS and BS from Texas A&M University in 1981 and 1980, respectively, all in Aerospace Engineering. He has also taught classes at the University of California, Irvine in the MAE Department.

  • Mr. Ken Knopp and Mr. David Westlund
  • Federal Aviation Administration
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Oct. 13, 2014 – The FAA conducts R&D in several area with the objective of improving safety, capacity, efficiency as well as environmental sustainability. The Aviation Research Division located at the FAA’s William J. Hughes Technical Center manages research with a focus on improving the level of safety in civil aviation. The division includes the Structures and Propulsion Branch, Fire Safety Branch, the Human Factors Branch, the Airport Technology R&D Branch, and the Software and Systems Branch. This presentation will cover research conducted under the Structures and Propulsion Branch that includes work on advanced materials, propulsion systems, aviation fuels, airframe icing, continued airworthiness and other related areas. The presentation will cover the area of inspection technology in greater detail with coverage of future system capabilities. This will include a discussion of new materials being used in aircraft manufacturing and the critical question for certification.

Biography:

Ken Knopp was named to the position of Structures & Propulsion Branch Manager within the Aviation Research Division at the Federal Aviation Administration’s (FAA’s) William J. Hughes Technical Center in October 2012. In this capacity, he is responsible for the leadership and directions of a comprehensive research, development, test and evaluation and provides the basis for acquisitions and safety improvements implemented by specification, procedures, regulations or certifications.

Ken has over 25 years of technical expertise in the aviation industry. Ken has a broad range of experience in research, development, test and evaluation of structural integrity, structural safety, maintenance & inspection technology, aircraft icing, propulsion & fuels, advanced materials, structural safety, aircraft catastrophic failure, fire safety and more. He has also provided strategy and direction in defining, communicating and implementing a broad spectrum of new agency management policies and initiatives.

Prior to 2012, Ken was manager of the Program Management Branch in the Aviation Research Division. He was responsible for oversight of all research activities in the Aviation Research Division ranging from aircraft safety, airports and human factors.

Ken is an active pilot with Commercial ratings in both fixed-wing and rotorcraft. He is a current member of American Institute for Aeronautics and Astronautics (AIAA), Society of Automotive Engineers (SAE) and Program Management Institute (PMI). He holds a Project Management Professional status with PMI. He holds a bachelor’s degree in aerospace engineering from Wichita State University and has completed graduate courses in aviation safety, management and project/program management.

David Westlund is currently the program manager for maintenance and inspection research in the structures and materials section of the Federal Aviation Administration’s Aviation Research Division. Prior to that he worked in the FAA’s Advanced Materials and Structural Safety research group where he was involved in research in the areas of adhesive bonding, environmental factors, and advanced materials processing. Currently he is active in research in non-destructive testing of composites as well as advanced control systems for commercial aircraft.

David has a bachelor’s degree in composite materials engineering and is completing his master’s degree in aerospace engineering from North Carolina State University this spring. He has industrial experience in manufacturing of composites as well as in composite material supply. His personal area of interest is flight dynamics and aeroservoelasticity.

  • Dr. Mathieu Kemp
  • Bluefin Robotics Corporation
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Oct. 6, 2014 – Increased maturity of Unmanned Underwater Vehicles and severe budget pressures within DoD is causing a scope explosion of UUV technology away from the traditional mine countermeasure and oil&gas survey missions. The presentation will discuss three active projects that illustrate this change: tracking of surface assets from extreme depths, dual-arm underwater manipulation, and UUV reference designs.

Biography:

Dr. Mathieu Kemp is the Director of Concept Development with Bluefin Robotics Corporation. He holds a PhD in Physics (UNC-Chapel Hill), and has 15 years of experience in subsea robotics.

He was previously the Director of Concept Development with Nekton Research, where he developed the oscillating fin UUV (ONR), the Ranger micro-UUV (DARPA), the data bubble (ONR), and the expendable sonar array (PMS 403). Following Nekton, he returned to academia as a guest researcher at Duke University, where he developed array signal processing algorithms for acoustically-competent robots. He joined Bluefin Robotics in 2010, and has since initiated research programs in ASW (DARPA), mine neutralization (ONR), and next-generation UUV design (DARPA).

Dr. Kemp holds five patents in underwater robotics, and is the author of 30 peer-reviewed articles.

  • Dr. Yi Chao
  • Remote Sensing Solutions, Inc. / Seatrec, Inc.
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Kevin Wang

Sept. 29, 2014 – This talk will describe a new stand-alone power system to harvest temperature differentials from the environment. This is a unique power solution in remote areas where solar energy is not available, and is the only power source underwater in the absence of wind and wave energy. The current state-of-the-art autonomous underwater vehicles are all powered by primary battery, and therefore have limited lifetime and can carry only limited sensors. Harvesting the ocean thermal energy associated with vertical temperature differentials between the warm surface and cold deep water has the potential to power these autonomous vehicles and sensors indefinitely. Recent results from the development, deployment and recovery of a prototype thermal recharging underwater float (known as SOLO-TREC) in the ocean will be presented. With eight hours energy harvesting and sampling interval, SOLO-TREC has made more than a thousand dives between the ocean surface and 500 meters water depth over a period of 1.5 years. Plans to commercialize this SOLO-TREC thermal recharging technology in support of several climate and oceanographic initiatives will be presented. Potential applications of this thermal energy harvesting technology to power autonomous vehicles and sensors on land and ice will also be discussed.

Biography:

Dr. Yi Chao is now the President and Chief Executive Officer (CEO) of Seatrec, Inc. He obtained his Ph.D. degree from Princeton University in 1990, and was a postdoc fellow at UCLA during 1990-1993. During 1993-2011, Dr. Chao worked at NASA’s Jet Propulsion Laboratory (JPL) on a variety of research projects ranging from ocean science, satellite remote sensing, numerical modeling, and underwater technology development. Dr. Chao was the Project Scientist during 2003-2011 for the Aquarius mission ($300M NASA investment to launch the first salinity satellite), and responsible for science, interface with technology and engineering implementation leading to the successful satellite launch in June 2011. Dr. Chao also has management experience working as a group supervisor (managing more than 10 FTEs) during 2005-2006 and section managers (managing more than 70 FTEs) during 2007-2009. Dr. Chao initiated the ocean thermal energy harvesting project at JPL in 2005. He was the Principal Investigator (PI) for the seed funding from JPL through a Research and Technology Development fund during 2005-2007. He was the PI for the SOLO-TREC project funded by the Office of Naval Research (ONR) during 2008-2011, and the PI for the follow-on project Slocum-TREC until his departure from JPL in January 2012 to establish Seatrec, Inc. to commercialize the thermal energy harvesting technology. Currently, Dr. Chao is also affiliated with University of California at Los Angeles as an Adjunct Professor, and with Remote Sensing Solutions as a Principal Scientist.

  • Dr. Behcet Acikmese
  • University of Texas at Austin
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Sept. 15, 2014 – Many future engineering applications will require dramatic increases in our existing Autonomous Control capabilities. These include robotic sample return missions to planets, comets, and asteroids, formation flying spacecraft applications, applications utilizing swarms of autonomous agents, unmanned aerial, ground, and underwater vehicles, and autonomous commercial robotic applications. A key control challenge for many autonomous systems is to achieve the performance goals safely with minimal resource use in the presence of mission constraints and uncertainties. In principle these problems can be formulated and solved as optimization problems. The challenge is solving them reliably onboard the autonomous system in real time.

Our research has provided new analytical results that enabled the formulation of many autonomous control problems in a convex optimization framework, i.e., convexification of the control problem. The main mathematical theory used in achieving convexification is the duality theory of optimization. Duality theory manifests itself as Pontryagin's Maximum Principle in infinite dimensional optimization problems and as KKT conditions in finite dimensional parameter optimization problems. Both theories were instrumental in our developments. Our analytical framework also allowed the computation of the precise bounds of performance for a control system, e.g., the bounds of agility for a vehicle, so that we can make accurate quantification of the capabilities enabled. This proved to be an important step in rigorous V&V of the resulting control decision making algorithms.

This presentation introduces several real-world examples where this approach either produced dramatically improved performance over the heritage technology or enabled a new technology. A particularly important application is the fuel optimal control for planetary soft landing, whose complete solution has been an open problem since the Apollo Moon landings of 1960s. We developed a novel “lossless convexification" method of solution, which will enable the next generation planetary missions, such as Mars robotic sample return and manned missions. Another interesting example is Markov chain synthesis with temporal and spatial safety constraints.

Biography:

Dr. Behcet Acikmese is an Assistant Professor in the Department of Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin. He received his Ph.D. in Aerospace Engineering from Purdue University. He joined NASA Jet Propulsion Laboratory (JPL) in 2003. He was a senior technologist at JPL and a lecturer in GALCIT at Caltech. At JPL, Dr. Acikmese developed control algorithms for planetary landing, formation flying spacecraft, and asteroid and comet sample return missions. He was the developer of the “flyaway" control algorithms in Mars Science Laboratory, which successfully landed on Mars in August 2012, and the reaction control system (RCS) control algorithms for NASA SMAP mission, which will be own in 2014. Dr. Acikmese developed a novel real-time convex optimization based planetary landing guidance algorithm that was flight tested by NASA JPL, which is a first demonstration of a real-time optimization algorithm for onboard guidance of a rocket, showing dramatic performance improvements over the existing state-of-the-art techniques. Dr. Acikmese is an Associate Fellow of AIAA and a senior member of IEEE.

  • Dr. Joseph Calantoni
  • Stennis Space Center
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Heng Xiao

Sept. 8, 2014 – We propose a new paradigm for multiscale modeling of fluid-sediment boundary layer flows with the goal of producing highly accurate and highly efficient forecasting of the complexity of the natural environment across operational length and time scales. The assumption that computing technology will never allow us to perform direct numerical simulations (DNS) of the natural environment often limits our ambition in forward thinking model development and produces only incremental improvements in the state-of-the-art technology. Regional and global forecasting models for earth, ocean, and atmospheric processes based on averaged equations (e.g., RANS) must advance beyond simple closures relations obtained for single-phase fluid turbulence (e.g., k‑epsilon, k‑omega, and Mellor-Yamada). We propose using a hierarchy of computationally intensive, high fidelity simulations to resolve subgrid processes across a range of cascading length and time scales in the model domain to generate numerical interpolations for the unresolved physical processes in the fluid-sediment boundary layer. As an example, we present a hierarchy of models developed for studying sediment dynamics at different scales. At sub-particle scales we use DNS to explicitly model turbulent fluid-particle interactions; the DNS is limited to O (1000) particles. At particle scales we use the discrete element method (DEM) for the sediment phase coupled to a RANS fluid model. The DEM-RANS simulation is used to simulate intermediate scales with spatially uniform conditions such as in sheet flow transport. At bedform scales, a mixture model (SedMix3D) exploits closures for mixture viscosity, diffusivity, sedimentation rates and particle pressure. The mixture model is used to simulate the coupling of bedforms and coherent vortex structures in the turbulent boundary layer. At each scale of interest, we will show comparisons of model results with laboratory and/or field measurements. Pathways for connecting simulations across length and time scales will be discussed.

Biography:

Dr. Joseph Calantoni is a research physicist and head of the Sediment Dynamics Section in the Marine Geosciences Division of the Naval Research Laboratory at Stennis Space Center (NRL-SSC), Mississippi. The Sediment Dynamics Section performs basic and applied research leading to advanced technology development, and demonstration and validation efforts focused around the physical, mechanical, and acoustical properties of seafloor, estuarine, and riverine sediments through a combination of high performance computing simulations and numerical modeling, detailed laboratory measurements, and field experiments. He received an undergraduate degree from the Pennsylvania State University and master’s and doctoral degrees from North Carolina State University all in physics. He was granted a National Research Council Research Associateship Award and began working as a postdoctoral fellow at NRL immediately after defending his dissertation in late 2002. Dr. Calantoni is internationally recognized for his novel approach to sediment transport modeling and simulation where the motions and interactions of every grain of sand are directly computed. Since August of 2009, he also has been acting as the National Defense Education Program (NDEP) site coordinator for NRL-SSC. He has initiated and oversees a K-12 education outreach program to promote science, technology, engineering, and mathematics (STEM) in the classroom.

  • Dr. Eric Paterson and Dr. Christopher Roy
  • Virginia Polytechnic Institute and State University
  • 104D Surge Building
  • 4:00 p.m.

Aug. 25, 2014 – The seminar will provide an update on the state of the department from the AOE Department Head and a review of guidelines for graduate students from the Graduate Program Director. This first seminar will be used to address current or recent issues related to scholarly ethics and integrity, including examples from the AOE Department and from the larger academic community. Attendance at this seminar is mandatory.

  • Dr. Matthew Kuester
  • Texas A&M University
  • 331 Randolph Hall
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport

Aug. 4, 2014 – Surface roughness can affect boundary layer transition (from laminar to turbulent flow) by acting as a receptivity mechanism for transient growth. Some of the work in the field of roughnessinduced transient growth predicts a “shielding” effect, where smaller distributed roughness displaces the boundary layer away from the wall and shields larger roughness peaks from the incoming boundary layer. The present work describes an experiment specifically designed to study this shielding effect. Three roughness configurations, a deterministic distributed roughness patch, a discrete roughness element, and a combination of the two, were manufactured using rapid prototyping and installed flush with the wall in a laminar flat plate boundary layer. Naphthalene flow visualization and hotwire anemometry were used to characterize the boundary layer in the wakes of the different roughness configurations. The distributed roughness initiated small amplitude steady disturbances that underwent transient growth. The discrete roughness element created a set of high‐ and low‐speed streaks in the boundary layer at a subcritical Reynolds number (Rek = Ukk/ν = 151) and tripped the boundary layer at a higher Reynolds number (Rek = 220). When the distributed roughness was added around the discrete roughness, the wake amplitude decreased at the sub‐critical Reynolds number, and transition was delayed by two boundary layer thicknesses at the higher Reynolds number. This work documents the first detailed measurements of transient growth over streamwise‐extended distributed roughness and demonstrates that the shielding effect has the potential to delay roughness‐induced transition.

  • Dr. Con Doolan
  • University of Adelaide
  • 331 Randolph Hall
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport

June 9, 2014 – Understanding, measuring and predicting flow-induced noise generated by the interaction of turbulent flow with objects (such as the trailing edge of airfoils), remains a great technical and scientific challenge. This is because it combines interesting and complex physical processes such as aerodynamics, turbulence, acoustics and sometimes material properties. The noise generated is normally broadband in nature and while easily distinguishable in practical applications, it is hard to measure in a wind tunnel due to facility induced noise effects and sometimes low signal-to-noise ratio. It is also difficult to numerically simulate, given the high Reynolds numbers of many applications and the limitations of turbulence models used to approximate wall-bounded flows. This seminar will give an overview of the aeroacoustic research activities of the Flow and Noise Group at the University of Adelaide, and will focus on some recent research concerning trailing edge noise production and interacting bluff bodies. The talk will include a discussion of some methods of passive trailing edge noise control that have been inspired by owls, who are able to fly and hunt silently.

Biography:

Prof. Con Doolan leads the Flow and Noise Group at the University of Adelaide, whose focus is on understanding and controlling flow-induced noise in application areas such as jets, wind turbines, aircraft and submarines. He has a PhD in Aerospace Engineering from the University of Queensland and completed a postdoctoral position at the University of Glasgow and a Research Scientist position at DSTO before joining the University of Adelaide. He has combined his interests of unsteady compressible fluid dynamics and acoustics to study fundamental and applied research problems in aeroacoustics. His group currently has 9 postgraduates and 3 postdocs, has developed new experimental and numerical capabilities, and receives funding from the ARC, DSTO and ASC Pty Ltd, among others.

  • Dr. D. Todd Griffith
  • Sandia National Laboratories
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport

May 5, 2014 – Wind energy will continue to play a crucial role in providing clean, renewable energy for the expanding needs of the US market. In fact, a scenario has been developed to provide 20% of US electricity by 2030. Wind turbines are large, complicated machines that operate in a harsh, turbulent environment in remote locations. Advancements to the current state-of-the-art in wind energy technology have been achieved through empirical and analytical methods in the fields of aerodynamics, structural dynamics, controls, and materials; key discipline areas for aerospace structures development as well. Increasing the penetration of wind energy requires that the cost of electricity generated from wind turbines remain competitive in the marketplace – this is particularly true in the offshore environment.

This talk will provide an overview of Wind Energy Technology and recent wind turbine rotor blade research and development activities at Sandia National Laboratories. Ongoing blade research targeted for the offshore environment will be presented and includes design studies and aero-elastic stability assessment for large 100-meter length blades, design of novel vertical axis rotor technology for deep-water siting, and structural health and prognostics management approaches to improve autonomy and reduce maintenance costs.

Biography:

Dr. D. Todd Griffith is a Principal Member of the Technical Staff in the Wind and Water Power Technologies Department at Sandia National Laboratories. He is the Technical Lead for Sandia's Offshore Wind Energy Program. His research contributions include work in the areas of structural dynamics, field testing, large offshore rotor technology (Sandia 100-meter blade work, VAWT), and structural health monitoring methods for wind energy systems. Prior to coming to Sandia in 2005, he completed Ph.D. work at Texas A&M University in Aerospace Engineering. He is an Associate Fellow of AIAA.

Note: Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  • Dr. Jandro L. Abot
  • The Catholic University of America
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Gary Seidel

April 28, 2014 – Composite materials are widely used in aerospace structures and many applications because of their superior specific stiffness and strength respect to weight. However, monitoring their structural health still remains too complex and difficult to implement in an integrated and distributed manner. This presentation is about integrated structural health monitoring in polymeric and composite materials using carbon nanotube yarns. Carbon nanotubes are grown into arrays that can be drawn into webs and further twisted into yarns that contain thousands of carbon nanotubes in their cross-sections. These carbon nanotube yarns are lightweight, stiff, strong, ductile and electrically conductive fiber-like materials that we are studying as piezoimpedance-based sensors. The proven concept of real-time, integrated, and widely distributed damage detection and strain monitoring using carbon nanotube yarn sensors is presented including the latest experimental results. The coupled mechanical, electrical and thermal response of the carbon nanotube yarns is of significant importance for their use as sensors and recently obtained results are presented including a not-before observed negative piezoresistance response. The effect of composition and structure of the carbon nanotube yarns on that coupled response is also discussed. The present challenges and proposed approaches for robust real-time structural health monitoring that eventually leads to condition-based maintenance are outlined for a variety of components, devices, and structures.

Biography:

Dr. Jandro Abot is a Clinical Associate Professor in the Department of Mechanical Engineering, Director of the Intelligent Materials laboratory, and Director of International Engineering Program Development of the School of Engineering at The Catholic University of America. He was previously an Assistant Professor in the Department of Aerospace Engineering and Engineering Mechanics at the University of Cincinnati. Prior to that, he was a Postdoctoral Fellow at Northwestern University where he had received his Ph.D. and M.S. degrees in Theoretical and Applied Mechanics. Dr. Abot also holds a 6-year degree in Structural Engineering from the Universidad de la República in Montevideo, Uruguay. Dr. Abot’s expertise is on the science and technology of composite materials and structural health monitoring of structures using carbon nanotube-based sensors. Dr. Abot published more than 90 journal and proceeding papers and led research projects sponsored by AFOSR, NASA, and Fulbright and collaborated on projects sponsored by NSF, ONR, and industrial consortiums. Dr. Abot taught nineteen different engineering courses in Solid Mechanics, Materials Engineering, Experimental Mechanics and Introduction to Mechanical and Aerospace Engineering, always receiving very good students’ evaluations. Dr. Abot is always committed to mentoring undergraduate students in the framework of research projects, and actively engaged in many departmental and school service activities such as recruitment, accreditation and international programs.

  • Dr. Sung-Eun Kim
  • Naval Surface Warfare Center Carderock Division
  • 310 Kelley Hall
  • 9:00 a.m.
  • Faculty Host: Dr. Eric Paterson

April 24, 2014 – CFD nowadays is frequently called upon to tackle complex multi-physics and multi-disciplinary applications. The general-purpose CFD codes, in attempts to cater to these diverse needs, have become increasingly larger and more complex. Software complexity is a serious issue which many legacy CFD codes face today, negatively impacting their overall efficacy in terms of development, quality assurance, packaging, maintenance and extensions. We believe that modern software engineering practices realized by OOP in C++ will greatly facilitate collaborative development, quality assurance, deployment, maintenance, and extension of general-purpose CFD software.

The talk is concerned with a computational fluid dynamics framework under development at the NSWCCD aimed at ship hydrodynamics as target applications. The framework has been built around OpenFOAM (Weller et al., 1998), an open-source CFD software tool-kit written in C++ that draws heavily upon object-oriented programming (OOP). The speaker will give an overview of the development effort that has been underway at the NSWCCD in the areas of ship hydrodynamics including discretization schemes, solution algorithms, turbulence, cavitation, free-surface flows, and fluid-structure interaction.

Biography:

Dr. Sung-Eun Kim works for the Hydromechanics Department of the NSWCCD in West Bethesda, MD, heading the Computational Hydromechanics R & D Branch. Before taking the current position, Dr. Kim had worked for Fluent Inc. as the FLUENT Product Manager and the Principal Engineer. He got the B.S. and M.Sc. from the Department of Naval Architect at the Seoul National University in South Korea, and the Ph. D. from the Department of Mechanical Engineering at the University of Iowa in 1991. Dr. Kim has been involved in numerous CFD development and research projects throughout his career, in the areas of RANS turbulence modeling, LES, finite-volume discretization, solution algorithms, and a broad range of aerodynamics and ship hydrodynamics applications including resistance, propulsion, maneuvering, cavitation, flow-induced noise, and fluid-structure interaction.

  • Mr. Steven M. Iden
  • Aerospace Systems Directorate, Air Force Research Laboratory, Wright-Patterson AFB
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

April 17, 2014 –

  • Dr. Jae-Hung Han
  • Korea Advanced Institute of Science and Technology
  • 216 Randolph Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Michael Philen and Dr. Seongim Choi

Nature’s flyers have fascinated human beings; we have dreamt of “flying freely” in the sky just like a bird. It is not surprising that most of the early trials for “flying machines” adopted flapping mechanism for generating thrust and/or lift; typical examples of early design of flapping vehicles can be seen in the sketches of da Vinci and Cayley. After humanity’s long unquenched thirst of bird-like flight had first been realized by the “powered fixed-wing flight” of the Wright brothers, flapping flight seemed to have been forgotten due to the great success of fixed-wing aviation. However, we now see the rebirth of flapping flying machines in much smaller scale, namely flapping-wing micro aerial vehicles (FWMAV). Equipped with a small video camera and various sensors, they can be used for surveillance and reconnaissance missions with perfect camouflage due to their size and inherent nature-like appearance. However, there exist several key technological hurdles which have not reached the level of nature’s flyers. Particularly, flying insects and birds possess unsurpassable maneuverability and stability over any micro air vehicles (MAVs) developed by humankind. This superiority in their flight performance has stimulated many researchers to investigate the underlying mechanics of their flight, ultimately to utilize the knowledge for our own platforms to perform in the same way. This talk introduces our recent efforts to understand flapping-wing flight and to develop flapping air vehicles. Particularly, the flight dynamics characteristics of flapping-wing air vehicles will be introduced and compared with those of nature’s flyers. Finally, a new wind tunnel test method, named PFE (pseudo flight environment) will be introduced for efficient system identification, controller design and performance verification of MAV.

Biography:

Dr. Jae-Hung Han is a professor in the department of aerospace Engineering, KAIST (Korea Advanced Institute of Science Technology), Korea. He is the director of Smart Systems and Structures Lab. (http://sss.kaist.ac.kr) and KARPE (KAIST Arena Real-time Positioning Environment). He received a B.S. in the department of mechanical department, KAIST in 1991. He received his M.S. and Ph.D. in the department of aerospace engineering, KAIST in 1993 and 1998, respectively. Before joining KAIST as a faculty member in 2003, he worked at the Institute of Fluid Science, Tohoku Univ., Japan and at the communication satellite development center of ETRI (Electronics and Telecommunications Research Institute), Korea. His research and teaching activities have focused on the development of new technologies and systems that utilize the smart materials and structures, and information technology (electronics) with the emphases on elegant design and reliable control. Recent research topics include Shape Reconstruction of Structures Using FBG Sensors; Dimensional Stability of Space Structures; Micro Vibration Suppression for Jitter mitigation; Bio-inspired Flying Robot, and so on. He is a senior member of AIAA, a member of ASME and SPIE. He has published about 90 international journal papers, and has received several awards including the best paper award in 2010 World Automation Congress (Sep., Kobe, Japan) and KAIST Creative Teaching award in 2007. He is an associate editor or a member of editorial board for 5 int. journals including Aerospace Science and Technology, Smart and Nano Materials, Advanced Composite Materials. He is currently in his sabbatical leave at Univ. Maryland.

  • Dr. Jaiwon Shin
  • NASA Aeronautics Research Mission Directorate
  • 321 McBryde Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Seongim Choi

April 15, 2014 – NASA recently developed a new and compelling strategic vision for the Aeronautics Research programs. This strategy is the culmination of a multi-year effort that included gathering industry and other Government agencies’ inputs, systems analysis of environmental and market trends, and the identification of societal mega-drivers. The trend analysis indicated that NASA could best contribute to the nation’s future societal and economic vitality by focusing efforts in six thrust areas. These six areas align to be responsive to a growing demand for mobility, severe challenges to sustainability of energy and the environment, and technology advances in information, communications, and automation technologies. The thrust areas are:

  • Assured autonomy for aviation transformation
  • Innovation in commercial supersonic aircraft
  • Ultra-efficient commercial vehicles
  • Transition to low-carbon propulsion
  • Real-time system safety assurance
  • Safe, efficient growth in global operations

To most effectively manage the research needed to address these strategic thrusts, NASA restructured its research programs, focusing on three specific goals. Dr. Shin will elaborate the research focus area on the goals.

Biography:

Dr. Jaiwon Shin is the associate administrator for the NASA Aeronautics Research Mission Directorate. In this position, he manages the agency’s aeronautics research portfolio and guides its strategic direction. Shin co-chairs the National Science & Technology Council’s Aeronautics Science & Technology Subcommittee. Between May 2004 and January 2008, Shin served as deputy associate administrator for the Aeronautics Research Mission Directorate where he was instrumental in restructuring NASA’s program to focus on fundamental research and better align with the nation’s Next Generation Air Transportation System (NextGen). Prior to coming to work at NASA Headquarters, Shin served as chief of the Aeronautics Office at NASA’s Glenn Research Center. Prior to that, Shin served as chief of the Aviation Safety Program Office, as well as the deputy program manager for NASA’s Aviation Safety Program and Airspace Systems Program.

Dr. Shin received his doctorate in mechanical engineering from the Virginia Tech, Blacksburg, Virginia. His bachelor’s degree is from Yonsei University in Korea and his master’s degree is in mechanical engineering from the California State University, Long Beach. His many honors include the 2008 Presidential Rank Award for Meritorious Senior Executive, NASA’s Outstanding Leadership Medal, NASA’s Exceptional Service Medal, a NASA Group Achievement Award, Lewis Superior Accomplishment Award, three Lewis Group Achievement Awards, and an Air Force Team Award.

  • Dr. Stewart A. L. Glegg
  • Florida Atlantic University
  • Holden Auditorium
  • 4:00 p.m.
  • Seminar Host: CREATe

April 14, 2014 – The noise from wind or water turbines present some unique operational issues that remain a challenge for the designer. The environmental impact of these systems can restrict the placement of wind turbine farms and impose operational restrictions that reduce their power output. This seminar will discuss how wind or water turbine noise is generated. It will be shown that the sound is primarily caused by flow over the blades. Modulation effects can be caused by the motion of the blades, the wind shear in the atmospheric boundary layer, and intermittent blade stall. The relative importance of these mechanisms will be discussed. We will also review the mechanisms of underwater sound generation for offshore systems, and the possible impacts that this may have on wind or water turbine operations.

Biography:

Dr. Stewart A.L. Glegg received his Ph.D. from the Institute of Sound and Vibration Research, Southampton University, U.K. in 1979 for studies in acoustics. He was a research specialist with Westland Helicopters, U.K. for two years (1977-1979) and then joined the Institute for Sound and Vibration Research, Southampton University (1979-1985) as a faculty member sponsored by the Navy working on Hydroacoustics. In 1985 he joined the faculty in the Department of Ocean Engineering at Florida Atlantic University. He was a Visiting Scholar at Scripps Institute of Oceanography in 1991, and from 2001 until 2003 he was Chairman of the Department of Ocean Engineering at Florida Atlantic University, and Director of SeaTech. He is currently the Director of the Center for Acoustics and Vibration at FAU. He is an Associate Fellow of the American Institute for Aeronautics and Astronautics, and a member of the Acoustical Society of America, the American Helicopter Society, SNAME, and ASME. He was an Associate Editor for the AIAA Journal (1994-97) and serves on the editorial board of the Journal of Sound and Vibration. In May 2004 he was awarded the American Institute for Aeronautics and Astronautics Aeroacoustics Award for "Outstanding contributions to the understanding and reduction of fan noise in turbo machinery". He has published over 140 technical papers in leading scientific and engineering journals including the Proceedings of the Royal Society, Nature, the Journal of Sound and Vibration, the Journal of the Acoustical Society of America and the AIAA Journal.

  • Dr. Carl Ollivier-Gooch
  • The University of British Columbia
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Christopher Roy

April 7, 2014 – The Advanced Numerical Simulation Laboratory at UBC focuses on algorithm development for CFD, with an application focus in compressible aerodynamics. We are currently working in three main areas: numerical methods for flow solution on unstructured meshes; generation of unstructured meshes; and the interaction between mesh quality and solution accuracy. We use unstructured meshes to be able to handle complex geometries, and high-order accurate finite-volume methods to get very accurate answers.

We have a very efficient high-order finite-volume solution scheme for unstructured meshes, and are currently working to extend this approach to turbulent flows around aircraft. Our work in unstructured mesh generation is aimed at improving mesh quality, robustness, and scalability to large problem sizes (and therefore to massively parallel computer architectures). Finally, we are developing new analysis techniques to study the accuracy and stability of unstructured mesh finite volume methods, with the ultimate goal of improving discretization schemes, mesh generation, and a posteriori error estimation.

The talk will give an overview of this work, with emphasis on several open questions in error estimation and reduction.

Biography:

Dr. Carl Ollivier-Gooch received his Bachelor of Science in Mechanical Engineering from Rice University (1988) and his Master's of Science (1990) and Ph.D. (1994) from Stanford University. He got his start working with unstructured meshes while a post-doc at NASA Ames Research Center (1994-95), and first started working in earnest on mesh generation as a post-doc at the DOE's Argonne National Laboratory (1995-96). He has been a faculty member in Mechanical Engineering at the University of British Columbia since 1997. In addition to his research work, Carl also coordinates the department's award-winning unified second year program, Mech 2.

  • Dr. Tim Lieuwen
  • Georgia Institute of Technology
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

March 31, 2014 – Major progress has been made over the last decade in quantitative understanding of how premixed flames respond to flow oscillations. Understanding these interactions is critical in order to understand the factors controlling combustion instabilities, which have emerged as one of the leading challenges associated with low NOx combustion technologies. This talk will describe the key processes controlling the flame response - flame anchoring, excitation of wrinkles by flow oscillations, tangential convection of wrinkles upon the flame, and kinematic restoration- and also show that different processes dominate in the near, mid-, and farfield of the flame.

Biography:

Dr. Tim Lieuwen is a Professor in the School of Aerospace Engineering and the Executive Director of the Strategic Energy Institute at Georgia Tech. Prof. Lieuwen is a top international authority on clean energy, particularly low emissions combustion. He has authored or edited 4 combustion books, including the textbook "Unsteady Combustor Physics". He has also authored 7 book chapters, 90 journal articles in leading journals, and over 170 other papers, and received 3 patents. He is a member of the National Petroleum Counsel and is Editor-in-chief of an American Institute of Aeronautics and Astronautics book series. Dr. Lieuwen is a board member of the ASME International Gas Turbine Institute, and is past chair of the Combustion, Fuels, and Emissions technical committee of the American Society of Mechanical Engineers. He is also an associate editor of Combustion Science and Technology and the Proceedings of the Combustion Institute, and has served as associate editor for the AIAA Journal of Propulsion and Power. Prof. Lieuwen is a Fellow of the ASME, an Associate Fellow of AIAA, and has been a recipient of the AIAA Lawrence Sperry Award and the ASME Westinghouse Silver Medal. Other awards include ASME best paper awards, Sigma Xi Young Faculty Award, and the NSF CAREER award.

  • Dr. Michael Martin
  • Louisiana State University
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Leigh McCue-Weil

March 24, 2014 – As micro- and nano-structures are integrated into devices, scaling issues, including the breakdown of the continuum limit for gas flows, determine the performance of the device. Accurate simulation of these devices requires not only using gas flow and thermal models that include these effects, but integrating continuum breakdown model with simulations of conduction heat transfer within the device, and thermo-mechanical and thermo-electrical effects.

This talk begins by looking at nano-mechanical devices built around suspended nanowires. Free-molecular models for the gas flow and heat transfer are combined with structural, thermal, and electrical models to predict the performance of the devices. We then continue to cover momentum and heat transfer through arrays of carbon-nanotubes, where the variety of length scales encountered ranges from the continuum to the free-molecular.

A related set of issues is encountered in the thermal actuation of micro- and nano-bridges. We look at two cases- using a steady heat input for device positioning, and using a sinusoidal heat addition to create a vibration in the system. The devices obey a macro-scale non-dimensional scaling law. However, nano-scale effects such as a pressure-sensitive heat transfer coefficient, and thermal vibration of the molecules of the bridge, still play a large role in determining the performance of the system.

In the rarefied gas regime, flows are also affected by surface properties. At the free molecular limit, shear stress, pressure, and heat transfer depend on molecular collisions at the surface. The nature of the collision is captured using accommodation coefficients. However, these accommodation coefficients are not well characterized. An experimental method for measuring these coefficients, and preliminary results, will be presented.

Biography:

Dr. Michael James Martin is an Assistant Professor of Mechanical Engineering at Louisiana State University in Baton Rouge, LA. He completed his Bachelor’s in Mechanical Engineering at the University of Florida and a M.S. in Mechanical Engineering, a M.A. in East Asian Studies, and a Ph.D. in Aerospace Engineering at the University of Michigan. While in graduate school, he was a visiting researcher at Hitachi’s Mechanical Engineering Research Laboratory and a Science and Technology Policy Fellow at the National Academies. He joined the LSU faculty in 2008 after post-doctoral work at the Naval Research Laboratory in Washington, D.C. He has also spent two summers as a NASA-JPL Faculty Fellow in the Micro Devices Laboratory at the Jet Propulsion Laboratory in Pasadena, CA. His research interests include micro-scale heat transfer and fluid mechanics, rarefied gas dynamics, and space systems design. He is an associate fellow of the AIAA, and a member of the ASME and APS.

  • Dr. Danielle Moreau
  • University of Adelaide
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport

March 17, 2014 – Junction flows occur when a boundary layer encounters a wall-mounted obstacle and are a source of unwanted noise for a wide range of engineering applications that include air, water, and land vehicles, wind turbines and turbomachinery. To investigate this flow-induced noise source, the sound produced by two types of junction flows will be examined in this seminar: a wall-mounted finite length cylinder and a wall-mounted finite length airfoil. Noise and flow measurements have been taken in an anechoic wind tunnel at the University of Adelaide at a range of flow speeds and for a variety of aspect ratios (length to cylinder diameter or airfoil thickness ratio) to determine the influence of these parameters on flow topology and noise generation. The experimental data give improved insight into the underlying sound generation physics and can be used to validate numerical predictions of junction flow noise.

Biography:

Dr. Danielle Moreau is a postdoctoral research associate with the Flow and Noise Group at the School of Mechanical Engineering at the University of Adelaide. She obtained her Ph.D. from the University of Adelaide in 2010 and was awarded a University Postdoctoral Research Medal for her Ph.D. research on virtual sensing in active noise control. Danielle's current field of research is experimental aeroacoustics and focuses on the understanding and control of flow-induced noise. She has more than 50 research publications and is currently a visiting Fulbright Scholar at Virginia Tech.

March 10, 2014 – Classes are not in session from March 8th to March 16th in observation of Spring Break.

  • Dr. Tianfeng Lu
  • University of Connecticut
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Feb. 24, 2014 – Recent progress in supercomputing and computational fluid dynamics (CFD) made it feasible to include realistic chemistry and detailed transport of simple fuels in high-fidelity flame simulations, e.g. the petascale direct numerical simulations (DNS) at Sandia National Laboratories, leading to an unprecedented predicting capability for turbulent reacting flows. However, major challenges remain for multidimensional simulations with practical engine fuels. Chemistry of such large hydrocarbons as gasoline, diesel and kerosene may involve hundreds of species and thousands of elementary reactions, and is computationally prohibitive for 2-D and 3-D simulations. Furthermore, the massive simulation data, which can be measured in petabytes, render it difficult to extract salient information from the simulation results. In response to these challenges, different approaches for mechanism reduction, including directed relation graph (DRG), analytically solved linearized quasi steady state approximations, and dynamic chemical stiffness removal, will be presented for systematic generation of compact, accurate and non-stiff chemistry of practical engine fuels that is amenable for large scale combustion simulations. Furthermore, the methods of chemical explosive mode analysis (CEMA) and bifurcation analysis will be presented for systematic identification of critical flame features, such as ignition, extinction, flame instabilities and flame fronts in complex flame configurations at laminar and turbulent, premixed and non-premixed conditions. CEMA will be demonstrated with recent DNS data for lifted jet flames, homogeneous charge compression ignition (HCCI) combustion, and temporal jet flames.

Biography:

Dr. Lu received his B.S. and M.S. in Engineering Mechanics from Tsinghua University in 1994 and 1997, respectively, and Ph.D. in Mechanical and Aerospace Engineering from Princeton University in 2004. Since then he has been a postdoctoral fellow and a research staff at Princeton. He joined the Department of Mechanical Engineering in the University of Connecticut as an Assistant Professor in 2008. Lu’s primary research interest is in combustion and computational fluid dynamics with special interests in chemical kinetics and computational flame diagnostics. He is a member of the Combustion Institute, an Associate Fellow of the AIAA, and the recipient of the inaugural Irvin Glassman young investigator award from the Eastern States Section of the Combustion Institute.

  • Mr. Thomas Garrett
  • NAVAIR
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Feb. 19, 2014 – Abstract: To Be Announced

  • Dr. Paul Bevilaqua
  • SkunkWorks
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Feb. 17, 2014 – The F-35 Joint Strike Fighter is a single aircraft developed to meet the multirole fighter requirements of the US Air Force, Navy, Marine Corps, and our allies. The Air Force variant is a supersonic, single engine stealth fighter. The Navy variant has a larger wing and more robust structure in order to operate from an aircraft carrier, while the Marine Corps variant incorporates an innovative propulsion system that can be switched from a turbofan cycle to a turboshaft cycle for vertical takeoff and landing. This novel propulsion system enabled the X-35 demonstrator to become the first aircraft in history to fly at supersonic speeds, hover, and land vertically. The F-35 program grew out of a design study of a supersonic replacement for the AV-8 Harrier, through the absorption of several other tactical aircraft initiatives. It became an international program with engineers from half a dozen countries developing a replacement for multiple aircraft types.

Biography:

Dr. Paul Bevilaqua has spent much of his career developing Vertical Take Off and Landing aircraft. He joined Lockheed Martin as the Chief Aeronautical Scientist and became Chief Engineer of the Skunk Works, where he played a leading role in creating the Joint Strike Fighter. He invented the dual cycle propulsion system that made it possible to build a stealthy supersonic VSTOL Strike Fighter, and suggested that conventional and naval variants of this aircraft could be developed for all three services. He then led the engineering team that demonstrated the feasibility of building such an aircraft.

Prior to joining Lockheed Martin, he was Manager of Advanced Programs at Rockwell International’s Navy aircraft plant, where he led the design of VSTOL interceptor and transport aircraft. He began his career as an Air Force officer at Wright Patterson AFB, where he developed an ejector lift system for an Air Force VSTOL Search and Rescue Aircraft.

He is a Fellow of the American Institute of Aeronautics and Astronautics, and a member of the National Academy of Engineering. He has received numerous awards including AIAA, SAE, ASME, and AHS Aircraft Design Awards, USAF Scientific Achievement Award, Lockheed Martin AeroStar and Nova Awards, and the Design Magazine’s “Engineer of the Year” award.

Paul received a BS in Aerospace Engineering from the University of Notre Dame and MS and PhD degrees in Aeronautics from Purdue University. He was also awarded an honorary doctorate from Cranfield University in the UK.

  • Dr. Jonathan Pitt
  • The Pennsylvania State University
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Feb. 10, 2014 – The Applied Research Laboratory at The Pennsylvania State University has been actively working on projects involving Fluid-Structure Interaction (FSI) for nearly a decade. This research area is a natural extension of several core competencies at ARL, namely existing expertise in high-Reynolds number CFD simulations, experimental fluid dynamics, and dynamic structural and acoustics modeling. This presentation will cover the history of FSI efforts in the Fluids, Structural Mechanics, and Acoustics Office at ARL/PSU, including both computational and experimental advances. Several of our current and past programs will be highlighted. Each of the computational tools that have been developed for modeling the interaction of dynamic fluid flows around deformable structures will be detailed. In particular, we will highlight our overset-grid enabled partitioned FSI solver, which leverages unique technological capabilities developed at ARL/PSU. In-house experimental efforts towards the validation of FSI simulations will be emphasized as well. The talk will conclude by highlighting several ongoing student projects.

Biography:

Dr. Jonathan Pitt began his studies at Lebanon Valley College, in Annville, PA, where he double majored in Physics and Mathematics. He then earned his M.S. in Engineering Mechanics, and subsequently his Ph.D. in Engineering Science and Mechanics, at The Pennsylvania State University. During his doctoral work, Dr. Pitt was awarded a Science, Mathematics, and Research for Transformation (SMART) Fellowship from the Department of Defense, and after defending, began work as a Research Physical Scientist in the Signature Physics Branch at the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (ERDC-CRREL) in Hanover, NH. Since June of 2010, Dr. Pitt has held the position of Research Associate at the Penn State Applied Research Laboratory (ARL/PSU), where he works in the Computational Mechanics Division. In addition to his research, Dr. Pitt holds an appointment as an Assistant Professor of Engineering Science and Mechanics at Penn State, where he advises several students and teaches advanced engineering mathematics. Dr. Pitt's research interests include computational mechanics (both fluids and solids) and the numerical solution of PDE, as well as topics from continuum mechanics, including continuum damage mechanics, thermoelasticity, and failure of brittle materials. Recently, he has been involved in ongoing efforts involving the modeling of fully-coupled fluid-structure interaction, and large scale ocean current hydrodynamics simulations.

  • Dr. Lin Ma
  • Virginia Polytechnic Institute and State University
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Feb. 3, 2014 – The study of modern combustion and propulsion systems calls for innovative and effective experimental methods. This seminar presentation will discuss several new laser diagnostics for flow and combustion imaging. These diagnostics all evolve around the three-dimensional (3D) and high-speed imaging of chemically reactive flows. It has been widely recognized that such diagnostic capability is solely needed to understand the complicated turbulence-chemical interactions, a long standing scientific problem with profound practical applications. This presentation will focus specifically on two approaches to enable such diagnostic capability: multidimensional temperature and chemical species measurement using absorption and emission tomography. These techniques are expected to enable instantaneous 3D imaging of key parameters with high temporal resolution, and provide experimental data long desired for the study of combustion and propulsion systems.

Biography:

Dr. Lin Ma received a B.S. in Thermal Engineering from the Tsinghua University in 2000, and M.S. and Ph.D. degrees in Mechanical Engineering from Stanford University in 2001 and 2006, respectively. He started his academic career in 2006 after completing his Ph.D. work, focusing on multidimensional laser diagnostics. His work on 2D mixture fraction measurement was recongized by the National Science Foundation with a CAREER award. He is also active in teaching and professional services. His teaching and research efforts were recognized by a Board of Trustee Award. He is an AIAA associate fellow and an active technical committee member for several professional organizations.

  • Mr. Harold Youngren
  • Aerocraft
  • Holden Auditorium
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Jan. 27, 2014 – The 34th America’s Cup was recently held in September 2013 in San Francisco in a new class of high-speed, hydrofoiling, wing-masted AC72 catamarans, capable of speeds up to 50 knots. The Cup was finally won by Oracle Team USA in a hotly contested, exciting race series against the very strong Emirates Team New Zealand challenger.

Mr. Harold Youngren was a member of the design team for Emirates Team New Zealand for the 2013 Cup campaign. He and his associate, Mr. Len Imas, were involved in many aspects of the aerodynamic and hydrodynamic design of the New Zealand AC72 catamaran. Mr. Youngren will review the design and development of the NZL-5 catamaran and discuss the hydrodynamic and aerodynamic challenges faced in creating and racing these novel and extreme racing yachts.

Biography:

Mr. Harold Youngren is a design consultant who has worked for a number of US aerospace companies over the last 30 years. His experience covers a wide range of aerospace design applications, principally on unmanned aircraft. His areas of interest include aircraft and rotorcraft design, propeller and ducted fan propulsion, stability and control, flight vehicle simulation, aeroelasticity and flutter. He has developed aerodynamic methods that are widely used in aircraft design, and has extensive experience with application of modern Computational Fluid Dynamics (CFD) methods for aerospace design.

In the 1980’s Mr. Youngren worked at Lockheed-California Company and the Skunk Works in aerodynamics and methods development. In 1987-1988 he left Lockheed to be the chief engineer for the MIT Daedalus human-powered aircraft. He was the chief aerodynamicist for the Frontier Systems/ Loral/ Boeing Tier 2+ DARPA program and worked with Frontier Systems on the design and flight testing of the A160 Hummingbird helicopter. More recent work includes tilt-rotor design with Karem Aircraft for the Army Joint Heavy Lift program and aerodynamic/hydrodynamic design for Emirates Team New Zealand on their America’s Cup boats (2011-2013).

Mr. Youngren earned both B.S. and M.S. degrees in Aeronautical Engineering from the Massachusetts Institute of Technology.

  • Dr. Leifur Leifsson
  • Reykjavik University
  • 118C Surge Building
  • 3:30 p.m.
  • Faculty Host: Dr. Joseph Schetz

Jan. 21, 2014 – The use of optimization methods in the aerodynamic design process, as a design support tool or for automated design, has now become commonplace. The use of high-fidelity methods, coupled with optimization techniques, has led to improved design efficiency. Although simulation-driven aerodynamic design optimization has progressed much in the last decades, it still involves numerous challenges. One of the biggest issues is that high-fidelity computational fluid dynamics simulations are computationally expensive. At the same time, conventional optimization techniques usually require a large number of simulations. Therefore, direct design optimization of high-fidelity models using traditional gradient-based techniques can be prohibitive, even with adjoint sensitivity information. Variable-fidelity optimization methods have shown to be efficient and can offer significant savings in computational cost. In this talk, recent progress in aerodynamic shape optimization using variable-fidelity models will be reviewed. Applications to the design of transonic and low-speed airfoils and wings are presented.

Biography:

Dr. Leifur Leifsson received a Ph.D. in Aerospace Engineering from Virginia Polytechnic Institute and State University in 2006. He is currently an Associate Professor with the School of Science and Engineering at Reykjavik University in Iceland. His research is focused on surrogate-based modeling and optimization.

  • Dr. Tom Shih
  • Purdue University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Dec. 9, 2013 – Although computational fluid dynamics and heat transfer (CFD/HT) has advanced tremendously over the past few decades, serious concerns remain on the accuracy of its solutions. This is because CFD/HT, like any tool, whether mathematical or experimental, has inherent sources of errors. This talk will start with two simple examples on validation of CFD/HT, illustrating capabilities and limitations of well-known turbulence models via steady & unsteady RANS and to show when LES is truly needed. Since the integrity of the validation process depends on the integrity of the experimental data, uncertainties associated with steady and unsteady measurements of the heat transfer are discussed and some solutions proposed. Also, uncertainties associated with Newton's Law of Cooling and the usefulness of scaling dimensionless parameters are discussed.

  • Dr. Qiqi Wang
  • Massachusetts Institute of Technology
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Dec. 2, 2013 – Many dynamical systems of scientific and engineering importance are unsteady and chaotic. These systems can be found in unsteady fluid flows around airplanes and inside gas turbine engines, aero-elastic oscillations, our climate system and molecular dynamics. This talk presents an adventure beyond just performing simulation of chaotic systems, towards aspects of computational engineering. These include optimization, control, uncertainty quantification, and data based inference. Our first focus is on sensitivity analysis, a widely used tool in computational engineering that calculates derivatives of simulation outputs to input parameters.

We show that existing methods for sensitivity analysis often fail in chaotic systems. The inability to exchange a limit and a derivative is the mathematical reason of this failure. A new computational algorithms for solving this challenge is the "least squares shadowing" method. We show many interesting aspects of this new method. We present application of this new method to several chaotic dynamical systems, including preliminary results on chaotic fluid flow systems and aeroelastic oscillations.

Nov. 25, 2013 –

Classes are not in session from November 23rd to December 1st in observation of Thanksgiving Break.
  • Dr. Sanjay Lall
  • Stanford University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Mazen Farhood

Nov. 11, 2013 – For centralized control systems, one of the major simplifying ideas is the separation principle, which states that one can make optimal choices of control actions based only on estimates of the system state. We discuss how this changes for multiplayer control systems, and give new simple separation principles which work in this setting.

  • Dr. Kevin Kinzie
  • General Electric Power and Water
  • 310 ICTAS
  • 4:15 p.m.
  • Faculty Host: Dr. William Devenport

Nov. 6, 2013 – Over the last decade, the installed wind energy capacity in the US has increased by a factor of 100 with a current capability of 60 GW generated by 45,000 turbine. That is enough energy to power the equivalent of roughly 15 million American homes. Wind power has been a US success story fueled by technology, R&D, and innovation. This presentation will present some basic foundations of wind energy and show how the industry has developed and is evolving into the future. A technology emphasis will be placed on aerodynamic and acoustics of the rotor and detailed concepts for wind turbine sound mitigation that are under development at GE Wind Energy will be shown.

  • Mr. Colin Adams
  • University of New Mexico
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Nov. 4, 2013 – Studies of laboratory plasmas are important to advances in many fields, including astrophysics, propulsion, and fusion. The parameter space of laboratory plasmas varies widely, covering a factor of roughly 10^5 in temperature and more than a factor of 10^20 in density. Plasmas generated by a spacecraft thruster typically have an ion density of only 10^10 particles per cubic meter or less, while a laser-driven fusion experiment could have well in excess of 10^30. The parameter space for astrophysical plasmas covers even lower densities, down to only 100 particles per cubic meter in the interstellar medium. This presentation will focus on two laboratory experiments. The first investigates flow-stabilization in a plasma confinement configuration applicable to a Z-pinch fusion thruster concept, which could one day be used for a high-speed deep-space mission. The second attempts to emulate and understand the physical processes involved in astrophysical collisionless shocks, which are thought to accelerate particles to high energies, a mechanism perhaps responsible for 40% of cosmic rays in the universe. The experiments which will be discussed have temperatures ranging from 1 - 300 electronvolts and densities from 10^19 - 10^23 particles per cubic meter. The diagnostic instruments utilized to understand the state and dynamic behavior of the plasma will be discussed, as well as the challenges of covering even this relatively limited range of plasma parameters.

  • Dr. Alex Ghosh
  • CU Aerospace & University of Illinois at Urbana-Champaign
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Oct. 28, 2013 – Small CubeSat-class satellites are opening up new avenues for science and technology development within the space industry. What was once a purely educational tool has quickly become the newest international exploration platform for low earth orbit missions. These sub-10 kg satellites ride into space as tertiary payloads, kicked out of their launch vehicles after all other satellites have reached their target orbit, and are left to survive in whatever ride-share provided orbit they are deposited into. Due to their small mass and volume, it has been infeasible until very recently to put any form of on-board propulsion on these spacecraft without a significant sacrifice of the science objectives. Because of the atypical combination of low-thrust with high propellant mass consumption, a new toolset is needed to assist with planning of both single and cooperative multi-satellite missions.

  • Dr. Steven Walker
  • DARPA
  • 3100 Torgersen Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Oct. 25, 2013 – Dr. Walker will share his unique perspective on the workings and culture of the Defense Advanced Research Projects Agency. DARPA’s mission is to maintain the technological superiority of the U.S. military and prevent technological surprise from harming our national security by sponsoring revolutionary, high-payoff research bridging the gap between fundamental discoveries and their military use.

Over the years, DARPA has worked to enhance our national security by funding research and technology development that not only have improved our military capabilities but have changed the way we live. Since the very beginning, DARPA has been the place for people with innovative ideas that lead to groundbreaking discoveries.

  • Dr. Andrew Sinclair
  • Auburn University
  • 110 Holden Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Oct. 24, 2013 – Modern spacecraft missions increasingly call for multiple, agile spacecraft interacting in a local environment. Over the past decades, multiple descriptions of the relative-motion dynamics for spacecraft formations have been developed using a variety of state representations, and considering both nonlinear and linearized equations of motion. This talk will focus on two recent advancements in spacecraft relative motion. The first is a calibration technique that greatly improves the domain of validity for linearized solutions. The second shows how the Clohessy-Wiltshire equations, originally derived for relative motion in circular orbits, can actually be extended to elliptic orbits. These insights enable further development of guidance, navigation, and control of spacecraft formations.

  • Dr. Jonathan Black
  • Air Force Institute of Technology
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Oct. 21, 2013 –

The Responsive Orbits group in the Center for Space Research and Assurance in the Aeronautics and Astronautics. Department at the Air Force Institute of Technology (AFIT) investigates short-term satellite missions that require frequent maneuvers. Responsive orbital maneuvers are being investigated for on-demand coverage, persistent dynamic orbit change, conjunction avoidance, and LEO-GEO transfers with fly-bys. This presentation will detail recent work in the optimization of responsive orbital maneuvers, orbit determination of such maneuvering spacecraft, and other current trends in space research.

  • Dr. Francis Valentinis
  • Defense Science and Technology Organization (DSTO)
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Leigh McCue-Weil

Oct. 14, 2013 – In any engineering design process, the perspective from which a design is viewed can have a significant impact on the degree of success of the result. In this seminar, a novel controller design for tracking of orientation and speed of an under-actuated slender-hull unmanned underwater vehicle (UUV) will be described. Rather than tracking the variables of interest directly, the energy of the system will be shaped in order to achieve the desired result. The control technique used is based on Port-Hamiltonian theory, an approach that can be closely related to bond graph theory, which is used for modeling of multi-domain system dynamics. In the control design presented, the target dynamics (desired dynamic response) is shaped with particular attention to the target mass matrix so that the influence of the un-actuated dynamics on the controlled system is suppressed. This results in achievable dynamics independent of uncontrolled states. Throughout the design, insight of the physical phenomena involved is used to propose the desired target dynamics. This approach is taken further in some subsequent examples. Firstly, it will be demonstrated how a further change of coordinates can lead to a control design featuring integral action. Subsequently, some preliminary results will be described showing how guidance control for the under-actuated vehicle can be achieved.

  • Dr. Luciano Castillo
  • Texas Tech University
  • 310 Kelly Hall
  • 2:00 p.m.
  • Faculty Host: Dr. William Devenport

Oct. 8, 2013 – During the first portion of this seminar, extensive PIV data collected from a scaled down 3 blade, 3 x 5 turbine array is shown. In order to understand how large-scales motions play a role in providing mean kinetic energy (MKE) to the array, low dimensional tools based on a proper orthogonal decomposition (POD) are used to analyze the spatially developing velocity field inside the scaled array. From this analysis, modal decomposition of the Reynolds stresses and fluxes of the MKE are constructed. Thus, from these modal expansions it is established that low order modes have large contributions to Reynolds shear stress regardless of analysis domain. In addition, it will be shown that mean kinetic energy transport resulting from Reynolds shear stress typically serves to bring energy into the array while transport terms associated with Reynolds wall-normal stress typically removes energy from the array. Furthermore, it will be shown that the sum of the first 13 modes for the mean fluxes contributes 75% of the total Reynolds shear stress in the domain.

The concept of coherent transfers of energy is employed here as means to uncover the scales responsible for the entrainment of mean kinetic energy into the array. The major contributions to the MKE entrainment are achieved by large-scale motions associated with sums of the Reynolds shear stress, (idiosyncratic) modes. Thus, the sum of the first 9 modes yield 54% of the total energy entrainment, with scales given by L ~ 13D associated with this sum. From these results, it is clear that scales of the order of the total wind farm size are those, which are critical in determining how much power can be extracted from the atmospheric boundary layer. In addition, during this seminar it will be shown that dispersive stresses are also important in the energy entrainment and dissipation in wind arrays with complex topography and where proximity between turbines exists.

  • Mr. Keith Englander
  • Missile Defense Agency
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Sept. 30, 2013 – Within the Missile Defense Agency we design, develop, test and field a number of different systems. These utilize technologies from directed energy to kinetic hit-to-kill, optical to RF sensors, and sea-based to space based. After fifteen years within the MDA engineering community a number of lessons have been learned that can prepare you for an engineering career. This presentation will discuss the lessons learned and ways to help to prepare you for the future.

  • Dr. James Driscoll
  • University of Michigan, Ann Arbor
  • 109 Surge Building
  • 1:00 p.m.
  • Faculty Host: Dr. Lin Ma

Sept. 30, 2013 – Three turbulent combustion experiments are discussed: (a) a lean premixed-prevaporized (LPP) gas turbine device that uses a GE TAPS fuel injector, (b) a scramjet experiment, and (c) our fundamental high Reynolds number HiPilot flame. Movies obtained using kilohertz laser imaging diagnostics allow us to assess some theoretical concepts that form the fundamentals of turbulent combustion theory.

In the gas turbine model combustor, the unsteady liftoff of the flame base leads to undesirable engine “growl”; measurements are explained by a simple Helmholtz model. In the scramjet and fundamental flames, we investigate the boundaries that define the regimes of thickened flamelets, broken flamelets and distributed reactions. These boundaries determine which subgrid modeling approach is most appropriate. The high speed imaging data also indicate how the theory of flame stretch and the theory of hydrodynamic instabilities apply to explain turbulent wrinkling of a flame surface and local flame extinction. The role of auto ignition chemistry becomes especially important in the highly-preheated air flows within the scramjet and gas turbine experiments. An “auto-ignition assisted flame” is observed, as evidenced by images of formaldehyde within distributed reaction zones that exist far upstream of the main heat release reactions. A jet-in-cross flow flame was studied in which a fuel jet is injected perpendicular to a heated high-speed air flow. Both distributed reactions and broken flamelets were observed. Some comparisons are presented of the Michigan measurements to DNS computational results obtained at LBL and Sandia Labs.

  • Dr. Neal Frink
  • NASA
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Sept. 23, 2013 – Dr. Neal Frink will be sharing a presentation that he gave for the Aerodynamics Award Lecture at the 2013 AIAA Applied Aerodynamics Conference in San Diego, June 24-27. The audience will be taken on an entertaining journey of how a youngster growing up through the 60’s, and seeded with a passion for things that fly, ended up on the crest of a new wave in CFD. This lecture will touch on some of the pivotal innovations that opened new doors in aerodynamic analysis and design. It is hoped that the listener will gain a better appreciation of how a relatively small number of pioneers were inspired with a level and breadth of innovation that collectively produced a true revolutionary advancement in computational aerodynamic capability.

  • Dr. Slade Gardner
  • Lockheed Martin Space Systems Company
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Sept. 16, 2013 – Advanced materials and manufacturing processes have been a hallmark feature in the legacy of Lockheed Martin products. There are many well established engineering heuristics for reducing the cost in manufacturing structures and there are operational philosophies that increase the capability or complexity of a manufactured article. One combination of heuristics and philosophies is to leverage existing and accepted manufacturing techniques with newly developed material formulations that can advantageously replace conventional high performance structures. In this presentation Dr. Gardner will discuss APEX, the thermoplastic nanocomposite which was strategically developed and implemented under his leadership with the goal of replacing aluminum structures with a material half the density at cost savings greater than 50%. By building a set of industry relevant performance goals from a strong knowledge of DoD system requirements the material formulation development had specific and achievable targets. Of manufacturing and economic importance is the flexible range of processing that allows a variety of manufacturing techniques to be used with a single formulation. This attention to customer specific needs amplifies the benefits of APEX in an advanced manufacturing philosophy that has been demonstrated with successful engineering trades, some of which will be presented.

A relatively new combination of heuristics and philosophies allows additive manufacturing methods that are, by name material additive in nature, rather than subtractive, and provide opportunities to extend beyond conventionally accepted part geometry and design. Additive deposition of material is automated for reduction in touch labor which directly reduces part cost and features precise repeatability. Dr. Gardner’s team has developed and demonstrated unique additive manufacturing equipment and capabilities to include point wise composition control and scale-up with articulated robotic equipment. Lockheed Martin has ongoing developments in metallic and polymer/composite additive manufacturing with the goal of increasing capability and complexity of parts. The development and utility of these manufacturing processes will be presented.

  • Dr. Elisa Toulson
  • Michigan State University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Sept. 9, 2013 – Enhanced ignition technologies such as turbulent jet ignition can improve fuel consumption, reduce emissions, and improve combustion stability in internal combustion engines. Additionally, these technologies may also enable renewable fuels and fuel blends to be integrated with existing technologies, facilitating their introduction into the marketplace. Chemical kinetics modeling is another important area of study in renewable fuels combustion research. Alternative fuels such as biodiesel are presently receiving attention as potential substitutes for fossil fuels, as they can be renewable, carbon neutral and provide energy security. However, biodiesel oxidation chemistry is complicated to directly model and existing surrogate kinetic models are very large, making them computationally expensive. Reduced or skeletal chemical kinetic models of biofuels are one way forward in enabling CFD simulation of renewable fuel combustion. This type of modeling in conjunction with experimental research allows for an improved understanding of the combustion of new renewable fuels.

  • Dr. Fen Wu
  • North Carolina State University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Sept. 2, 2013 – The linear parameter-varying (LPV) plants are finite-dimensional linear systems with known, parameter-dependent state-space data. It is assumed that the parameters are measurable in real-time and thus available for control use. LPV models have been used to approximate nonlinear dynamics. The study of LPV control is motivated by the gain-scheduling design methodology in industrial practice, and provides a systematic approach for gain-scheduling control. In this talk, we will first give an overview of existing LPV control techniques.

Then we will address the gain-scheduling control synthesis problem for nonlinear systems. For nonlinear gain-scheduling control, the LPV model is obtained by plant linearization about zero-error trajectories upon which an LPV controller is synthesized. A key issue would be how to find a nonlinear output feedback compensator which can guarantee the closed-loop system of nonlinear plant and compensator linearizes to the interconnection of LPV model and LPV controller. Consequently, the stability and performance properties about the zero-error trajectories can be inherited when the nonlinear compensator is implemented. By incorporating equilibrium input and measured output into an auxiliary LPV model, the nonlinear compensation problem would satisfy the linearization requirement. Moreover, the compensator synthesis condition can be reformulated as linear matrix inequalities (LMIs) based on parameter-dependent Lyapunov functions (PDLF) and is solvable using convex optimization algorithms. The validity of the proposed approach will be demonstrated through a ball and beam design example.

  • Dr. Stefan Oerlemans
  • Siemens Wind Power
  • Location: 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport
  • Co-sponsored by the Center for Renewable Energy and Aerodynamic Testing (CREATe)

Aug. 26, 2013 – This seminar will present several aspects of wind turbine aeroacoustics. After an introduction about the industrial relevance of wind turbine noise, the different potential source mechanisms and their characteristics are discussed. The results of advanced field measurements will be presented to illustrate which noise sources are dominant for modern large wind turbines. Next, it will be described how noise from wind turbines can be predicted. Such prediction methods are important for the design of quiet wind turbines and for the planning of wind farms. Finally, different methods to reduce wind turbine noise will be presented.

  • Dr. Jorg Hohe
  • Fraunhofer-Institut für Werkstoffmechanik IWM
  • 209 Randolph Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

July 12, 2013 – Composite materials are indispensable materials in modern lightweight construction and many other technological fields. Consisting of two or more different constituents with different geometry and material properties, they offer the possibility for a design of tailored materials to comply with a large variety of requirements deriving from the intended structural application. A special case of composite materials are cellular solids and solid foams.

In engineering application, the numerical analysis of components and structures consisting of composite materials is preferably performed in terms of macroscopic, “effective” properties rather than by using detailed models of their microstructure. The macroscopic properties may be determined either experimentally or numerically using a numerical “homogenization” approach. The main advantage of the numerical schemes is that they can be employed in a rather efficient manner for the design of custom-made materials and in screening analyses for assessing the potential of competitive microstructural designs. Especially in complex tasks of multi-objective problems in the design of materials, the experimental expenses can be reduced significantly.

The presentation is concerned with schemes for a high-precision numerical prediction of effective properties of composite and cellular materials. In a first step, the basic concepts for determination of the effective mechanical properties from the analysis of a representative volume element are reviewed. Subsequently, some recent advances are discussed, covering the numerical prediction of effective thermal properties and thermo-mechanical coupling effects as well as a prediction of effective acoustic properties. A special case in the prediction of effective properties for composite materials is the prediction of the uncertainty and scatter induced by the geometrical uncertainty of disordered microstructures. For this purpose, a probabilistic homogenization procedure is presented. The application of the different approaches is illustrated by examples related to the design of materials for lightweight construction and power generation.

  • Mr. Mathias Emeneth
  • PACE America, Inc.
  • 210 Randolph Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

July 11, 2013 – Presentation and live-demonstration of the interactive aircraft preliminary design tool Pacelab APD. Based on a typical aircraft design case study the main features of Pacelab APD are shown covering all major areas such as aircraft configuration, weights & cg, aerodynamics, flight performance, economics, stability and control.

  • Mr. Steven Dobbs
  • California State Polytechnic University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

May 6, 2013 – Recent emphasis on developing extraordinary fuel efficient “green” aircraft are driving future aircraft designs toward higher and higher aspect ratio wings and tails to reduce drag and increase range. However, the inherent extreme flexibility or these wings will be more prone to aeroelastic problems such as coupled wing and body bending instabilities, aero-servoelastic instabilities, divergence, gust response, excessive deflections from hard landings, and flutter. The Cal Poly Pomona Aerospace Engineering department is involved in a series of student and faculty led experimental research projects to investigate the types of aeroelastic and structural dynamics design issues related to high aspect ratio wings. The multi-year experimental projects include active twist control of flexible composite wings for drag reduction, simulation of “free-flight’’ of a model in a wind tunnel for measurements of dynamic stability derivatives, development of a wind tunnel gust generation system, dynamic model gust response and active control for gust alleviation, buffet alleviation, flutter suppression, and the simultaneous implementation of multiple control laws. The projects include coordination with the Air Force Research Labs and Lockheed Martin Skunk Works for a model of the X-56A, and Boeing for a wing model of the Blended Wing Body aircraft. These current and future projects will be discussed including emphasis on developing wind tunnel testing and validation methods.

  • Dr. Lian Duan
  • National Institute of Aerospace
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Heng Xiao

April 29, 2013 – Improved energy efficiency is a high priority area for future aircraft vehicles. Prior studies have shown that reduction in drag can have a major impact on fuel burn. The general strategies for skin-friction drag reduction include laminar flow control to delay laminar-to-turbulent transition and turbulent flow control to reduce turbulent drag. In this talk, we first describe our general effort in laminar flow control and turbulent drag reduction. Then, we focus on turbulent drag reduction by riblets (biomimetically inspired micro-grooves), which have long been recognized as a premier approach for reducing skin-friction drag. Although their effectiveness in reducing drag has been extensively demonstrated in the subsonic regime, few studies have been conducted in the supersonic regime and none for hypersonic flows. Moreover, the detailed drag reduction mechanism has not been well understood, partly because of the difficulties in making measurements in the close vicinity of the grooves. High-fidelity simulations are used to assess the effectiveness of riblets in reducing drag at high speeds and elucidate the drag-reducing mechanism.

  • Dr. Bhuvana Srinivasan
  • Los Alamos National Laboratory
  • 1060 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. Lin Ma

April 22, 2013 – Two-fluid plasma models treat ions and electrons as two separate fluids and are necessary to study a number of problems relevant to fusion, propulsion, and other aerospace and space physics applications. Two-fluid plasma models are useful to study plasma propulsion, which is the most promising propulsion method for cargo and human deep space missions. A number of plasma propulsion concepts such as Z-pinch pulsed plasma thrusters, plasmoid acceleration through magnetic nozzles, Hall thrusters, and others require ions and electrons to be treated as separate species to accurately resolve the physics. This talk will study two-fluid instabilities in a Z-pinch and two-fluid physics in a field-reversed configuration plasmoid that are relevant to thruster concepts. In addition to studying the relevant physics with the intention of pursuing a working thruster, the power source required for long-term cargo and human missions remains a major hurdle. Fusion energy is a strong contender to meet this requirement, thus understanding the physics and mitigating the instabilities that stand in the way of achieving fusion ignition are a priority. Fluid instabilities such as the Rayleigh-Taylor instability are thought to result in turbulent mixing and energy loss in inertial confinement fusion, preventing the ignition of fusion fuels. This talk will present results to show that two-fluid plasma physics effects could be used to mitigate such turbulent mixing and energy loss, making fusion conditions more achievable. Numerical and computational challenges of using two-fluid plasma models will also be presented.

  • Dr. Alexey Shashurin
  • The George Washington University
  • 1060 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

April 18, 2013 – A low-mass, low-volume propulsion subsystem for small satellites that would provide attitude control and station keeping duties is one of the key area of interest for US Army and has high priority for NASA (Low Cost Access to Space program), NSF (CubeSat program) and other funding agencies. Propulsion systems based on electrically activated small thrusters that utilize chemically-inert solid propellants are beneficial for these applications. Micro-thrusters are able to deliver small impulse bits of about several mN×s to satellites and characterized by simplicity, scalability, low cost, low weight and high reliability. The central goal of this talk is to present our recent R&D advances in the field of micro-Cathode Arc Thruster (mCAT) and demonstrate its high potential for commercialization and application in future space missions.

The introductory part of this talk is about main principles of plasma utilization in electrical propulsion and, in particular, unique suitability of vacuum arc for propulsion applications. The main part of the presentation will start with brief consideration of operation principle of mCAT. We will discuss propellant feeding mechanism, electrical design of the system and analyze role of magnetic field to extend operational lifetime of the mCAT. In the next part of the talk we will give some details on recent studies of processes occurring in three regions, namely near the electrodes, inside the mCAT channel and in the exhaust jet. We will demonstrate rotation of the cathode spots along the cathode interface and corresponding rotation of the exhaust jet, effective transport of the flow through the thruster channel and its acceleration at expansion into vacuum. Measurements of thrust, specific impulse, propellant consumption rate, plasma parameters and back flux will be presented and discussed. In the end of the talk, we will consider comprehensive data of mCAT parameters and compare its performance with commercially available thrusters.

  • Dr. Thomas Jackson
  • University of Illinois at Urbana-Champaign
  • 1060 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

April 15, 2013 – This talk will address recent developments in the modeling and simulation of energetic materials, including solid propellants and explosives. We will also discuss multiscale issues, how to couple the mesoscale to the macroscale. Part of the work involves describing the microstructure, and we have developed a packing algorithm to generate the microstructure. Additional work involving the packing code will also be discussed.

  • Dr. Frederick Dryer
  • Princeton University
  • 316 Randolph Hall
  • 11:00 a.m.
  • Faculty Host: Dr. Rakesh Kapania

March 29, 2013 – The transportation energy sector, especially for aircraft, depends upon the use of liquid hydrocarbon fuels, principally because of their high energy density per unit volume, and air transportation is forecast to grow more rapidly than residential, industrial, and electric power sectors over this century. Energy security and global climate implications are major drivers for energy conservation, and the offset of fossil energy use by renewable fuel strategies. Reducing net carbon cycle and air pollutant emissions associated with air transportation is typically considered to be more difficult than for other energy sectors. Today, transportation is fueled principally by petroleum derived liquids, so efforts that are integrated appropriately with present fuel production, distribution, storage, and the current immense investment in legacy hardware are critical to achieving long term address of the economic and climate change drivers as well as to reducing our dependence on foreign oil imports. This presentation will discuss the complex nature of the transportation energy sector, particularly that for aircraft. We will consider the physical and chemical properties of real transportation fuels derived from petroleum, the present certification methods that designate fuels as fit-for-use as aircraft fuels, and how these issues impact the integration of new alternative fuels derived from non-petroleum resources.

The fact that all transportation fuels (jet aviation, diesel and gasoline) are complex mixtures of hundreds of chemical components of generally unknown molecular composition presents a significant challenge to formulating methodologies that characterize detailed, fuel-specific combustion/emissions responses to specific fuel properties. A formulation strategy using “surrogate fuel mixtures” that emulate well the fully vaporized global combustion behavior of a specific real jet fuel will be discussed and demonstrated. Surrogate mixtures and real fuel are shown to produce essentially the same fully prevaporized combustion properties provided that both materials share similar derived cetane number (DCN), hydrogen/carbon molar ratio (H/C), threshold sooting index (TSI) and average molecular weight (Mwave). The fundamental bases for this result will discussed and their relevance to the study multi-phase combustion phenomena and the relative importance of physical and chemical kinetic property emulations on applied combustion observations will be described. Implications to constructing robust chemical kinetic models for real fuel combustion predictions will also be described. Extension of findings to ground transportation fuels will also be discussed.

  • Dr. Dominic J. Piro
  • University of Michigan
  • 1060 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. Wayne Neu

March 28, 2013 – Both military and commercial ships experience harsh conditions at sea. Military vessels have experienced failures in the form of both buckling of decks and superstructure as well as fatigue damage. Impact loading, especially in the bow and on flat sterns, adds significant loading and introduces a ringing response in the vessel that reduces the fatigue life as well as causes immediate damage. As cargo vessels become larger, fluid-structure coupling becomes more important to consider in the design stage.

Current fluid-structure interaction technology in the marine industry is limited. Common hydroelastic analysis is performed with potential flow models coupled with structural solvers. These methods are fast, but do not account for wave-breaking or directly solve the three-dimensional slamming problem. Improved fluid modeling is possible with Computational Fluid Dynamics (CFD), however due to the expense of these methods the full coupled problem is not solved in practice. Therefore, an accurate and efficient fluid-structure interaction solver has been developed to analyze marine hydroelastic problems using CFD and a modal structure. Emphasis has been placed on accuracy, stability, and computational efficiency of the new method.

The current fluid-structure interaction solver has been used to analyze several problems. First a two-dimensional wedge section is studied to understand the sectional loading on a ship. The problem of constant-velocity elastic wedge impact has been used to validate the fluid-structure coupling. The new problem of the entry and exit of two-dimensional elastic wedge sections is then studied with solver. Moving to three dimensions, elastic ship problems are studied. The response of an elastic box-barge in oblique seas is used to validate the combined rigid-body and structural motions against experimental data. The JHSS segmented model tests performed at NSWCCD are used to validate the prediction of whipping response.

  • Dr. Sara Jabbarizadeh
  • American Bureau of Shipping
  • 1060 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. Leigh McCue-Weil

March 25, 2013 – Compared to polynomial discretization, representing the geometry using Computer Aided Design (CAD)-based functions can potentially help avoid geometrical inaccuracies that are common in conventional computational analysis methods. This is mainly due to the fact that CAD-based analysis uses an exact representation of the geometry instead of an approximation by meshing which in turn, eliminates the need for a rigorous meshing process that is necessary in classic Finite Element Analysis. Despite the advantages of this method, which is generally referred to as Isogeometric Analysis since it employs a single basis function both for representing the geometry and estimating the solution, it has its own unique challenges that need to be meticulously studied. To this end, this seminar covers topics from a doctoral research conducted at the University of Michigan which aimed to compare non-linear analyses of two-dimensional curved membranes under different loading conditions using analytical and numerical methods.

The Developed methods were applied to curved membranes that were used to model the skirt system of Air Cushion Vehicles (ACVs) made of non-stretchable flexible rubber-like materials. In particular, an analytical method was developed based on equilibrium equations for a specific geometry which related the tension in the membrane to the deformed geometry. These equations were solved using the Newton-Raphson Method. Also a classic Finite Element Method (FEM) was developed using the “stiffness influence coefficient method”, where elements were represented by arcs, and displacements of nodes were selected as degrees of freedom. In another method, the geometry was described using a quadratic Bezier curve. The Principle of Virtual Work was then applied which allowed for nonlinear stress-strain relationship and the application of non-conservative loads. To solve for large deformations, equilibrium equations were established for the current state. All constraints were applied using the Lagrange Multiplier method. In addition to inextensible membranes, elastic membranes were also studied using bending and stretching strain energy. By comparing results obtained from these methods, it was concluded that arc-element FEM was an accurate method of good convergence rate when compared with the other method although it had limitations when treating curves with low curvature sections. While the Bezier-based analysis overcame these limitations, it introduced the uneven movements of control points that should be treated with design optimization and regularization.

  • Dr. Kevin Guanyuan Wang
  • California Institute of Technology
  • 1060 Torgersen Hall
  • 5:00 p.m.
  • Faculty Host: Dr. Christopher Roy

March 21, 2013 – The dynamic interaction of a movable or deformable structure with the internal or surrounding fluid flow characterizes many important engineering problems. Examples include flexible marine propeller, marine current turbine, implosion of underwater structure, flapping wing micro aerial vehicle (MAV), and pipeline explosion, just to name a few. Currently, most fluid-structure interaction (FSI) problems with nonlinear dynamics (shock, turbulence, large structural deformation, etc.) and nonlinear material behaviors (plasticity, fracture, etc.) have not been thoroughly analyzed, which greatly hinders the advance of related engineering fields.

This lecture will first provide an overview of popular computational approaches for solving coupled fluid-structure systems: monolithic and partitioned procedures; deforming, immersed, and overset grids; synchronous and staggered time integrators. Emphasis will be placed on the development, validation, and application of a high-fidelity computational framework for FSI problems involving strong shocks, multi-material fluid flows, plastic structural deformations, and fluid-induced fracture. Key components of this framework include: (1) a localized, physically-based FSI model employed at fluidstructure interface; (2) conservative methods for transferring fluid-induced loads onto the wetted surface of the structure; (3) robust and efficient interface tracking and capturing methods; and (4) an extended finite element method (XFEM) for structures with dynamic
fracture.

The salient features of this computational framework will be highlighted in the full-scale, predictive simulations of several FSI problems in Aerospace and Ocean Engineering, including underwater explosion and implosion, flapping wing MAV, flexible aircrafts for high altitude long endurance (HALE) flight, and fighter jet maneuvers. Possible future research directions will be discussed at the end of this lecture.

March 4, 2013 –

  • Dr. Bernard Ferrier
  • NAVAIR
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Leigh McCue-Weil
The purpose of this Office of Naval Research originally sponsored Future Naval Capabilities UAV project is to demonstrate the feasibility to automatically signal the initiation of UAV descent. The current NAVAIR objective is to recover the UAV on-board a moving vessel within reasonable safety margins regardless of the seaway. The Energy Index, the operative component of the Landing Period Designator, identifies quiescent periods to initiate aircraft descent based on aircraft deck limit definitions. Dynamic Interface simulation provides the physical information from which initial deck limits might be derived. Energy Index quiescent indications for UAV recovery opportunities are presented outside of current operating limits. A brief synopsis of the theory and calculation of the ship motion simulation and Energy Index programs, are discussed. Undercarriage deflection to encountered deck forces and aircraft stability, were calculated. Using Launch and Recovery “rondelles” (or speed-polars), the deck limits at specific ship’s speeds may be identified. Impacts on the proposed deck limits, are discussed. Percent improvement of operational availability is demonstrated. The results using simulated data are compared to those recorded during dynamic interface testing at sea showing strong correlation between computational approaches.
  • Ms. Judy Bergmann
  • MIRATEK, Inc.
  • 321 McBryde Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Joseph Schetz

Feb. 26, 2013 – The presentation will be in two parts. The first part will provide a brief overview of wind tunnel basics and look at a selection of wind tunnel test types at AEDC (Arnold Engineering Development Complex), mostly performed in 16T, the 16-foot transonic wind tunnel. Some of the tests discussed date back to the early years of 16T, but most were more recent. The second part of the presentation highlights some of the current projects in hypersonics being overseen by Test and Evaluation/Science and Technology (T&E S&T), High-Speed Systems Test (HSST) of the DoD Test Resources Management Center (TRMC).

Wind tunnel testing dates back to the late 1800s. A basic wind tunnel was designed and used extensively by the Wright brothers in the first decade of the 1900s to refine the shape of the airfoil used on the first powered aircraft. The wind tunnels at AEDC provide some of the best flow quality and highest productivity of any in the world. Many types of tests are performed in the wind tunnels at AEDC, some considered typical, others less common. Basic wind tunnel operation is described along with several of the types of tests performed at AEDC.

The hypersonic flight regime has been studied and tested for more than 60 years. Developments in the past several years have advanced the state of the art significantly. T&E S&T is tasked with providing technical oversight of programs that devise methodologies for ground testing hypersonic flight regime technologies. Several of the projects that have been completed recently or are still in progress are described.

  • Dr. Carolyn Beck
  • University of Illinois at Urbana-Champaign
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Mazen Farhood

Feb. 25, 2013 – In this talk we present a computational framework for solving a large class of dynamic clustering and coverage control problems, ranging from those that arise in deployment of mobile sensor networks to identification of ensemble spike trains in neuronal data. This framework provides the ability to identify natural clusters in an underlying dynamic data set, and allows us to address inherent trade-offs such as those between cluster resolution and computational cost. More specifically, we define the problem of minimizing an instantaneous coverage metric as an optimization problem using a Maximum Entropy Principle formulation, constructed specifically for the dynamic setting. Locating cluster centers and tracking their associated dynamics is cast as a control design problem that ensures the algorithm achieves progressively better coverage with time.

  • Dr. Robert Lucht
  • Purdue University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Feb. 18, 2013 – Over the last several years we have developed high-pressure combustion test rigs with optical access with funding from private industry, NASA, and DOE. Both aviation gas turbine and power-generating gas turbine test rigs are presently operational. The design of the window assemblies for the high-pressure, high-temperature conditions encountered is described, along with lessons learned from our early design efforts. The operation of the facility and the integration of remotely operated laser diagnostic systems with the combustion test rigs are discussed in detail.

Recent measurements in these combustion facilities are discussed. The laser diagnostic methods that we have used to investigate high-pressure combusting flow fields include coherent anti-Stokes Raman scattering (CARS) and 5 kHz OH planar laser-induced fluorescence (PLIF) imaging. These methods were used recently to investigate the injection of natural gas/air jet into a subsonic vitiated crossflow at a pressure of 6 bar. Dual-pump H2/N2 CARS was used to measure the temperature field and the H2 CARS signal was used to indicate regions of high chemical reactivity. The same reacting flow field was also investigated using 5 kHz OH PLIF, and 5 kHz PIV measurements will be performed in the near future. Our recent work on the application of ultrafast laser systems for 5 kHz single-laser-shot CARS measurements will also be discussed.

  • Dr. Owen Brown
  • Kinsey Technical Services
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Troy Henderson

Feb. 11, 2013 – This seminar will provide an overview of DARPA's System F6 program and discuss the challenges and benefits of fractionated spacecraft architectures. System F6 is focused on development of technologies that will enable the fractionation of space systems. Fractionation is the networking of disaggregated satellites and ground nodes, wherein various software and hardware resources can be shared across the network. Cluster flight of space modules is a focus of the System F6 program - the navigation approach, as well as the novel software implementation of it, will be discussed.

  • Dr. Li Qiao
  • Purdue University
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Feb. 4, 2013 – Nanofluid fuels are liquid fuels with a stable suspension of nanometer-sized particles (e.g., energetic nanomaterials and nanocatalysts). Depending on the physical and chemical properties of the added nanomaterials, nanofluid fuels can achieve better performance, such as increased energy density, faster burning rate, easier and faster ignition, and enhanced catalytic effects. They can potentially be used for future hypersonic propulsion systems, which largely depend on the ability to use liquid fuels of high energy density, short ignition delay, and high reaction rate. Nanofluid fuels may also be used for power/thrust generation under special circumstances. For example, they can provide higher power or thrust for a longer time for compact systems where the volume of carried fuel is limited, such as an unmanned aerial vehicle (UAV) or a power MEMS. Furthermore, the nanofluid fuels containing various nanostructured ignition agents may allow for the distributed ignition of fuels using light sources, which could greatly improve combustion efficiencies, as opposed to conventional single-point ignition. Lastly, nanofluid fuels exhibit significantly enhanced mass and heat transport properties resulting from the random Brownian motion and the thermal radiation properties of nanoparticles, which could aid in combustion. This seminar will present our recent results on the research of tailored high-performance fuels using nanoscale energetic materials as additives. The effects of several parameters on fuel’s colloidal stability and combustion performance will be discussed, including particle material, loading rate, particle size, as well as the type of base fluid and the use of a surfactant. These understanding will provide important guidelines for the optimized use of nanomaterials in terms of material, surface functionalization, particle size, and concentration in liquid fuels to achieve the desired performance.

  • Dr. Stephen Clay
  • Wright Patterson Air Force Base
  • 1050 Torgersen Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Jan. 30, 2013 – Composite structures offer many advantages over conventional metallic structures, including higher specific strength and stiffness. These benefits should translate into lighter weight structures, but this is not always the case. For laminated polymer matrix composites, the matrix dominated out-of-plane properties and bearing strength are very low. To compensate, extra material and heavy mechanical fasteners are often applied to structural joints. Dr. Clay will discuss several of the emerging joining technologies being developed by the Air Force Research Lab and their industrial and university partners in order to overcome these shortcomings. Some of the techniques to be discussed include z-pinning, stitching, flocking, co-melding, and 3-D woven Pi preforms. An overview of the Air Force Research Lab will also be presented.

  • Dr. Karen M. B. Taminger
  • NASA Langley Research Center
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Jan. 28, 2013 – This lecture is intended to introduce the world of materials engineering and how this knowledge helps us manufacture airplanes, spacecraft and other useful objects. It will focus on an additive manufacturing process called “Electron Beam Freeform Fabrication (EBF3)”. We have been developing this process for ten years at NASA Langley, and it provides a good example of how an idea can be brought to reality and even demonstrated in zero gravity. The EBF3 process uses a focused electron beam in a vacuum environment to create a molten pool on a metallic substrate; then translated while metal wire is fed into the pool. A part is thus built directly from a CAD drawing in a layer-additive fashion. Because this is a layer-additive process, metal can be placed only where it is needed and the material chemistry and properties can be tailored throughout a single-piece structure. This allows new design methodologies such as integrated sensors, tailored structures, and complex, curvilinear stiffeners to be designed to support loads and perform other functions such as aeroelastic tailoring or acoustic dampening. All of this is made possible with modeling and simulation. This seminar will follow the maturation of the EBF3 technology from inception to commercialization and will describe how a manufacturing process can influence future aircraft designs by providing a solution that enables multidisciplinary optimization.

  • Dr. Matthew Orr
  • Configuration Design
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Joseph Schetz

Dec. 10, 2012 – This presentation will provide an overview of Boeing’s Commercial Airplanes (BCA) product development organization commercial airplane market forecast, and airplane development work. It will then cover what Configuration Design and Engineering Analysis (C&EA) group does at Boeing and discuss the key attributes of an airplane designer.

  • Dr. Lesley Weitz
  • The MITRE Corporation
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Dec. 3, 2012 – The FAA is in the midst of NextGen, which is a major overhaul of the nation’s air traffic system. A key part of NextGen is the deployment of Automatic Dependent Surveillance – Broadcast (ADS-B), which is a surveillance technology that relies on a satellite-based navigation source and a datalink to broadcast an aircraft’s state information. That information will be used by air traffic control on the ground and may be used by ADS-B-IN-equipped aircraft in the surrounding airspace. Avionics applications that take advantage of this increased information on the flight deck are currently being developed through avionics standards activities in the US and Europe.

Interval Management (IM) is just one of a number of efficiency- and safety-enhancing applications that are enabled by ADS-B. IM is a near-term operational concept that will provide more precise spacing between aircraft pairs. In an IM operation, the air traffic controller will instruct an “IM aircraft” to achieve and maintain a desired spacing interval relative to a “target aircraft”. The IM aircraft is equipped with avionics that provide the flight crew with speed commands to achieve and maintain the specified spacing interval relative to the other aircraft. IM operations are envisioned in a variety of environments where more precise spacing between aircraft will help the air traffic controller to meet operational goals (e.g., higher throughput at busy airports). IM is also expected to increase the opportunity for aircraft to fly more fuel-efficient trajectories.

This presentation will describe the IM application and some of the technical challenges that are being addressed in the ongoing development of avionics standards and ground automation to support Air Traffic Controllers.

  • Col. David Anhalt
  • Space Systems/Loral
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Troy Henderson

Nov. 26, 2012 – Hosted payloads are government mission capabilities that are integrated on commercial communication satellites. A government hosted payload performs specific government missions using resources provided by the commercial host platform.

Mr. Anhalt will speak about the role commercial satellites can play in hosting science payloads for NASA and military payloads for the Department of Defense. Concepts for commercially hosted payloads are part of a broader trend by government to increasingly rely on the commercial space sector for more of their goods and services. Federal budget pressures are forcing both the civil and national security sector to consider the economic advantages of leveraging the vibrant, productive commercial space sector.

The Space Age has spawned three distinct sectors of space activities: civil, national security, and commercial. While each sector trains their young professionals at the same engineering and business schools and often rotates talent in mid-career, the three sectors have nevertheless developed distinctly different cultures, business approaches, and preferences for solving their core problems.

Architecture has been defined as “the structure – in terms of components, connections, and constraints – of a product, process, or element.” (Dr. Eberhardt Rechtin, and Mark W. Maier, The Art of Systems Architecting.) By using the lens of systems architecture the speaker will identify underlying technical, programmatic and policy issues that impact the commercial hosting enterprise.

Additionally, the speaker will be available to answer question about the roles engineers play at satellite manufacturing companies like Space Systems/Loral in mission design, spacecraft development, manufacturing, test, operations and business development.

  • Dr. Noel Clemens
  • The University of Texas at Austin
  • Location: 112 Robeson Hall
  • Time: 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Nov. 12, 2012 – Ablation remains a topic of current interest in the aerospace community owing to the need to develop thermal protection systems for spacecraft that undergo entry into planetary atmospheres. Ablation is a complex multi-physics process that involves high-temperature thermochemistry, radiation, gas-surface interactions, turbulent transport, mechanical erosion, etc., all of which combine to make it quite a challenging process to study. A particularly important physical process that remains very difficult to model is the transport of ablation products in high-speed turbulent boundary layers that develop in the presence of surface roughness and strong pressure-gradients. The study of scalar transport is enabled by a new technique that has been developed at The University of Texas at Austin, which uses planar laser-induced fluorescence of the gas-phase products resulting from a sublimating ablator (naphthalene) exposed to a high-speed flow. In this presentation details of the technique will be discussed including measurements of the photo-physical properties of naphthalene such as the temperature variation of the absorption and quenching cross-sections. Such data are necessary to enable the use of the technique for quantitative measurements of the scalar concentration. Results will be shown for the application of the technique to study scalar dispersion in a Mach 5 boundary layer and to visualize ablation on a subscale space capsule model.

  • Dr. Jack Langelaan
  • The Pennsylvania State University
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Nov. 12, 2012 – In October 2011 Team Pipistrel-USA.comʼs electric powered Taurus G4 won the Green Flight Challenge, flying nearly 200 miles at an average ground speed of 107 miles per hour and an equivalent fuel efficiency of 403.5 passenger miles per gallon. This was the first demonstration of a practical general aviation mission (combining payload, speed, range, and endurance typical of GA) by an electric powered aircraft, and the achieved fuel efficiency is roughly six times better than that of typical general aviation aircraft (and twice that of a Toyota Prius).

This talk will discuss design of the G4, give an overview of its electric power system and describe the flight planning algorithms that were used during the competition.

  • Dr. Ella Atkins
  • University of Michigan
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Nov. 5, 2012 – Aircraft and spacecraft are now able to plan and autonomously execute task-level actions as well as optimizing and precisely following 4-dimensional trajectories. Automation has, however, struggled to effectively manage off-nominal situations, a particularly important capability when such events introduce increased risk of losing a costly vehicle or of causing harm to people or property. This presentation will describe Dr. Atkins’ long-term research in improving safety and robustness through autonomous contingency management with application to aircraft and spacecraft.

Spacecraft operate in a harsh environment, are costly to launch, and experience unavoidable communication delay and bandwidth constraints. The objective of the presented work is to optimize science goal achievement while identifying and managing encountered faults. The relative value of science data collection is traded with risk of failure to determine an optimal policy for mission execution. Our major innovation is to incorporate fault information based on the dynamics of the spacecraft and on the internal composition of the spacecraft. Approximate dynamic programming (ADP) is applied to address computational complexity challenges.

Dr. Atkins will also describe her long-term research in emergency flight management aimed at safely recovering and landing a disabled aircraft. Her research has focused on envelope-adaptive flight planning and guidance, with a more recent project focusing on flight safety assessment. Results from her research will improve safety in manned and unmanned aircraft, and are beginning to inform risk analysis and mitigation processes relevant for certification of small unmanned aircraft systems (UAS).

  • Dr. Scott Slocum
  • ExxonMobil Upstream Research Company
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Oct. 29, 2012 – Model tests of two different types and two different scales were performed with test cylinders fitted with a freely-rotating riser fairing. At lower flow speeds, both tests showed the fairings to be effective in suppressing vortex-induced vibration (VIV) of the cylinder and in reducing drag. In both tests, however, large lateral cylinder oscillations developed once the flow exceeded a certain critical speed. Motion amplitudes in one test significantly exceeded those of a bare pipe undergoing VIV. A simple two-dimensional model of aircraft wing flutter was used to better understand the cause of the oscillations and to relate the onset of the motion to the fairing's specific design characteristics. The model predicted the observed threshold speeds with reasonable accuracy, suggesting that riser designers can borrow from existing aerodynamic flutter theory to ensure that riser fairings are designed to remain dynamically stable over the range of current speeds expected in service.

  • Dr. James Brasseur
  • The Pennsylvania State University
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Oct. 22, 2012 – The design and control of future generations of advanced commercial wind turbines will benefit from detailed quantifications of the interactions between the turbulence within the lower atmospheric boundary layer and the large variations in stresses on the blade surfaces in time and along blade span. In particular, the more energetic turbulent motions in the atmospheric surface layer, the region dominated by commercial wind turbines, are of order the rotor disk in scale and vary in structure depending on atmospheric stability and surface topography. As these energetic atmospheric eddies sweep through the rotor disk, they change the magnitude and the angle-of-attack of the incoming velocity vector relative to the rotating blades, leading to rapid changes in blade surface boundary layer structure, large variability in surface stresses and, consequently, large temporal fluctuations in blade and shaft bending moments, shaft torque and turbine power. Consequences include reduced reliability through premature blade, bearing and gearbox failure, and suboptimal control strategies. I shall describe a DOE-funded program to develop the Penn State "Cyber Wind Facility," a unique ‘experimental’ capability using petascale computer resources and the latest technologies in high-performance computing to collect ‘data’ for advanced wind turbine research, analysis and design. By integrating high-fidelity large-eddy simulation of the atmospheric boundary layer with high-resolution hybrid URANS-LES, and by including blade elasticity, tower deformation, and platform-wave interactions in offshore configurations, the Cyber Wind Facility is conceptualized akin to a full-scale wind turbine field facility designed to generate the highest fidelity most well-resolved 4-D data possible simultaneously over the entire wind turbine domain, for both onshore and offshore wind turbines. Planned extensions include turbine-turbine interactions and the improvement of actuator line methods for wind farm simulation.

  • Dr. Dennis McLaughlin
  • The Pennsylvania State University
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. K. Todd Lowe

Oct. 15, 2012 – Penn State research addresses the need for jet noise reduction for modern military aircraft. The noise induced hearing loss suffered by Navy personnel working in close proximity to tactical aircraft, particularly for carrier-based operations, is of increasing concern to the US Navy. However, acoustic measurements for such exhaust jets are scarce, due to the cost involved in making full scale measurements and the lack of details about the exact geometry of the nozzles. Past efforts at Penn State University, in partnership with the NASA Glenn Research Center and GE Aviation, was focused on developing methodology for using data obtained from small and moderate scale experiments to reliably predict the most important components of full scale engine noise. The experimental results demonstrated good agreement between small scale and moderate scale jet acoustic data, as well as between heated jets and heat-simulated ones.

Our most recent efforts have developed a methodology and device for the reduction of supersonic jet noise. The goal is to develop a practical active noise reduction technique for low bypass ratio turbofan engines. The method involves precise blowing into the divergent section of the engine exhaust nozzle to produce fluidic inserts that mimic “hard walled” corrugated inserts. By altering the configuration and operating conditions of the fluidic inserts, active noise reduction for both mixing and shock noise has been obtained. Substantial noise reductions have been achieved for mixing noise in the maximum noise emission direction and in the forward arc for broadband shock-associated noise. To achieve these reductions (on the order of 5 and 2 dB for the two main components respectively) practically achievable levels of injection mass flow rates have been used. The total injected mass flow rates were less than 4 % of the core mass flow rate and the effective operating injection pressure ratio was maintained at or below the same level as the nozzle pressure ratio of the core flow. Refinement and optimization of this technique is being pursued at Penn State University.

  • Dr. P. D. Weidman
  • University of Colorado
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Oct. 8, 2012 – Equations modeling the shape of the Eiffel Tower are investigated. One model, based on equilibrium of moments, gives the wrong tower curvature. A second model, based on constancy of vertical axial stress, does provide a fair approximation to the tower's skyline profile of twenty-nine contiguous panels. However, neither model can be traced back to Eiffel's writings. Reported here is a new model embodying Eiffel's concern for wind loads on the tower, as documented in his communication to the French Civil Engineering Society on March 30, 1885. The result is a nonlinear, integro-differential equation which may be solved to yield an exponential profile. An analysis of actual panel coordinates reveals a profile closely approximated by two piecewise continuous exponentials with different growth rates. This is explained by specific safety factors for wind loading that Eiffel & Company incorporated in the design and construction of the free-standing tower.

  • Dr. Bjoern Kiefer
  • Technical University Dortmund
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Gary Seidel

Sept. 24, 2012 – Active and multifunctional materials have drawn considerable interest in recent years, as they show great potential for enabling novel sensing, actuation, transduction, energy harvesting and bio-mimetic applications, to be employed, for example, in aerospace, the automotive industry, microelectronics and the biomedical field. In addition to the exploration, synthesis and characterization of new material systems, the accurate modeling and simulation of their constitutive response is of key importance in the endeavor of leading the application development process beyond purely conceptual ideas.

We focus here on the modeling of a subclass of such materials exhibiting magneto-mechanical coupling, namely giant magnetostrictives, magnetic shape memory alloys and magneto-active polymers. From a modeling standpoint, great challenges stem from the complex coupled, nonlinear and inelastic nature of the material response. This macroscopic behavior is often driven by microstructural changes, such as phase transformations or twin-boundary and magnetic domain wall motion. On the other hand, strongly-coupled nonlinear boundary value problems must be solved for device analysis.

Three particular modeling cases are discussed and illustrated with numerical examples. First, as an extension of classical approaches of computational inelasticity, a return-mapping-based algorithm for magnetic shape memory behavior is presented. Secondly, a new and rather general variational-based modeling approach and computational implementation of macroscopic continuum magneto-mechanics is presented with a special focus on dissipative magnetostriction. Finally, a brief overview is given on recent research activities related to computational magnetomechanics in the geometrically-nonlinear setting with an application to magnetoactive polymers.

References

[1] B. Kiefer and D. C. Lagoudas, Modeling the Coupled Strain and Magnetization Response of Magnetic Shape Memory Alloys under Magnetomechanical Loading, Journal of Intelligent Material Systems and Structures Vol. 20, 143–170, 2009.

[2] C. Miehe, B. Kiefer and D. Rosato, An Incremental Variational Formulation of Dissipative Magnetostriction at the Macroscopic Continuum Level, International Journal of Solids and Structures Vol. 48, 1846–1866, 2011.

[3] B. Kiefer, T. Bartel and A. Menzel, Implementation of Numerical Integration Schemes for the Simulation of Magnetic SMA Constitutive Response, Smart Material and Structures Vol. 21, doi:10.1088/0964-1726/21/9/094007, 2012.

  • Dr. Owen Hughes
  • Virginia Polytechnic Institute and State University
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Sept. 17, 2012 – On Friday January 6, 2012 the speaker disembarked in Civitavecchia from a seven-day cruise on the Costa Concordia. Exactly one week later, on the night of January 13, the ship departed from Civitavecchia toward its first port of call, Savona. Two hours later, off the island of Giglio, it struck a submerged rock which tore an underwater gash 50 meters (161 feet) long on the port side, flooding several compartments including the engine room. The ship immediately lost all main engine power. A few minutes later it lost electricity and lights, but emergency generators restored both. At first the ship moved away from the land with a heel to port and gradually came to a stop. The ship was probably in a condition of “loll” because when the bow thrusters were used to turn the ship around, the 23 mile-per-hour onshore wind rolled the ship to a starboard heel and slowly pushed it toward the land. It finally grounded about an hour after the collision, only a few hundred meters from the port of Giglio. Eight minutes after grounding, the captain ordered abandon ship. Amid much confusion most of the 26 lifeboats were launched in about 30 minutes, but after this the increasing heel to starboard prevented any further launchings. Forty five minutes after grounding the ship capsized to starboard and the approximately 100 remaining passengers clung to the high side of the ship. The next morning they were removed by helicopter.

The seminar will give details about the accident and explain what is a “condition of loll”, which is why the ship heeled and capsized to starboard, even though the gash in the hull was on the port side.

The second part of the seminar will explain how the wreck is to be removed. It will be the largest righting and refloating operation in history, and will take about one year. The ship will then be towed to a shipyard and broken up. The ship cost about $600 million in 2004 dollars, and the removal of the wreck will cost about $300 million.

  • Dr. Robert Meakin
  • CREATE-AV
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Eric Paterson

Sept. 10, 2012 – The spectrum of engineering processes that span the design, development, deployment, and sustainment of air vehicles is vast and can usefully be referred to collectively as “aircraft acquisition”. The potential for multi-disciplinary, physics-based simulation modeling and High Performance Computing (HPC) to positively impact the engineering processes associated with aircraft acquisition is large. The argument put forward in this work is not the pitting of the traditional ground-based and flight test paradigm for generating needed engineering data against the capacity of physics-based simulation. Rather, it is to assert that multi-disciplinary, physics-based simulation and HPC, in combination with traditional means of generating engineering data, represent an opportunity to fundamentally change the paradigm for aircraft acquisition. The addition of physics-based simulation as a means to generate actionable engineering data enables increased capacity of the engineering workforce, reduced workloads through streamlined and more efficient workflows, and minimization of the need for rework due to an ability for early detection of design faults and aircraft performance anomalies.

Regardless of the source, in order for engineering data to be actionable, the data must be available when it is needed, correctly represent the governing physics, and be of quantifiable quality. While the preceding may appear to be a statement of the obvious, it implies a number of fundamental principles, the realization of which is nontrivial. Timeliness, physical accuracy, and uncertainty quantification are general headings. Each of these is essential to making effective programmatic decisions, but if one had to choose the most important, perhaps it would be timeliness. When the time comes to make a decision, the fact that “exact data might be available next week” is irrelevant. The decision is being made now. For example, a countdown in the launch of a spacecraft generally includes scheduled pauses to accommodate go/no go decision points. If system readiness data is not available at the scheduled time, the decision
maker will make a decision anyway – launch or delay. Launch if the decision maker deems the risk associated with the missing data to be small, or delay to await analysis and possibly the next launch window. A lack of timeliness associated with engineering data always has the effect of increasing risk and causing programmatic delays.

Decisions associated with aircraft acquisition, span engineering processes beginning with conceptual design and continuing through all subsequent phases of development, deployment, and sustainment of the final fleet of aircraft fielded. Paradoxically, decisions made at the earliest phases of acquisition are the most significant, setting overall development and life-cycle costs, yet they are currently supported by the lowest fidelity engineering data and highest uncertainties. The conundrum is compounded by the fact that design cycle-time trends inversely with position across the aircraft acquisition spectrum – meaning that not only do early-phase engineering decisions have long-term impacts, but the time available to generate needed engineering data to support the decisions is minimum. Herein lies the opportunity for physicsbased simulation and HPC to enable a paradigm change. Multi-disciplinary, physics-based simulation and HPC represent a capacity, through virtual testing, to generate needed engineering data at required levels of physical accuracy. Accordingly, the critical path to enabling a paradigm change depends most acutely on timeliness.

The present paper describes the role and technical details of a novel mesh paradigm that bridges a key technology gap on the path to realization of this vision. The paradigm is referred to as “strand mesh”. The paper introduces the strand mesh paradigm in context of a major multi-disciplinary, physics-based simulation software development project and an outline of the planned progression of capability development. Attributes of the mesh paradigm that warrant critical path designation are described along with key technology dependencies. The paper includes examples and a brief set of applications.

1 CREATE-AV Project Manager / IPA (University of Alabama at Birmingham), Associate Fellow AIAA

  • Dr. Jack McNamara
  • The Ohio State University
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Sept. 3, 2012 – Sustained, reusable hypersonic platforms have tantalized the research community for over 60 years. A significant limiting factor to success is a lack of understanding of the interaction of a vehicle with the extreme hypersonic environment. This has necessitated the use of high levels of conservatism when designing the structural system, leading to excessive weight penalties that prevent a responsive flight system. This seminar will discuss recent research aimed at increasing the scientific understanding of energy transfer between the structure and a hypersonic operating environment.

Aug. 6, 2012 – Speaker: Prof. Russell Cummings
Modeling and Simulation Research Center, U.S. Air Force Academy, Colorado

A new approach for computing the unsteady and nonlinear aerodynamic loads acting on a maneuvering aircraft is presented. This approach is based on Duhamel’s superposition integral using indicial (step) response functions. The novelty of this approach relies on the development of a time-dependent surrogate model that fits the relationship between flight conditions (Mach number and angle of attack) and indicial functions calculated from a limited number of simulations (samples). The aircraft studied in the current paper exhibit highly nonlinear roll moment and therefore a very large number of step functions need to be calculated to accurately predict the aerodynamic behavior at each instant of time spent in aircraft maneuvers. The reduced order model, along with the surrogate model, provide a mean for rapid calculation of step functions and predicting aerodynamic forces and moments during maneuvering flight. The maneuvers are generated using a time-optimal prediction code with the feasible solutions based on the vehicle control and state constraints. Results presented show that the developed surrogate model aids in reducing the overall computational cost to develop cost-effective reduced-order models. It is also demonstrated that the reduced order model used can accurately predict time-marching solutions of maneuvering aircraft, but with an advantage that reduced order model predictions only require on the order of a few seconds of computational time.

  • Dr. Heng Xiao
  • Institute of Fluid Dynamics
  • 221 Randolph Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Alan Brown

May 17, 2012 – Large-Eddy Simulation (LES) has gained successes in the past decades, particularly for free-shear flows. In wall-bounded flows, however, the computational cost of LES is very high in order to resolve the near-wall features. This is a major hurdle for the application of LES in industrial and practical flows.

In this talk, I will present a consistent hybrid framework for turbulence modeling. In this framework, the filtered equations and the Reynolds averaged Navier-Stokes (RANS) equations are solved simultaneously in the whole domain on their respective meshes. Consistency between the two solutions is achieved through additional drift forcing terms in the corresponding equations. Compared to current methods in the literature, this approach leads to very clean conditions at the LES/RANS interfaces. The results demonstrate that the hybrid solver leads to significantly improved results with minor computational overhead compared to traditional LES, making it a promising candidate for industrial flow simulations. On going development include: (1) coupling with high-accuracy Cartesian LES solvers, (2) application to more complex flow (e.g. flow around cylinder), and (3) using more advanced turbulence models such as Reynolds Stress Transport Models.

  • Dr. Goetz Bramesfeld
  • Saint Louis University
  • 118C Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

April 30, 2012 – The fact that UAVs can fly missions otherwise not feasible for manned aircraft, for example because of long durations or risky environments, has made such vehicles very popular among the U.S. Armed Forces. Although a missing regulatory body hampers the civilian/commercial application of UAVs, this is about to change with very recent legislative developments. It is for certain that by the end of this decade, we will see the wide application of UAVs for civilian and commercial purposes, often with missions that we can barely imagine right now. Small and micro aerial vehicles will clearly be an important part of this future development, primarily due to their low kinetic energy, thus less damage to others in cases of accidents, and the continuation of miniaturization of electronics, which enables even smaller and more powerful sensors. Nevertheless, in order to augment the performance of small UAVs and MAVs innovative approaches are needed to increase the utility of such vehicles. For the past ten years, Dr. Bramesfeld has been working on improving the aerodynamics and flight performance of small UAVs. This work includes the design and testing of a "foam-it-up" small UAV that is a highly portable, testing of passive high-lift enhancement devices, optimizing MAVs for indoor flight, and modeling the interaction of structures and aerodynamics.

  • Dr. Seongim Choi
  • Korea Advanced Institute of Science and Technology
  • 261 Durham Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

April 19, 2012 – This talk focuses on the development and application of the state-of-the-art design optimization methodologies in aerospace vehicle design. Through the design applications of both fixed and rotary wing vehicle designs, numerous aspects of design optimization methods are introduced and compared. First, multi-fidelity and multidisciplinary design optimization method for supersonic business jets (SBJ) is introduced. Optimal shape and mission profile of SBJ are sought to reduce sonic boom on the ground while increasing aerodynamic performance. Second, a new design methodology is introduced for helicopter rotor design at unsteady forward flight. Unlike the fixed wing vehicle design, numerous difficulties are associated with the accurate prediction and design of unsteady rotor flows. A time-spectral and adjoint-based analysis and design method is introduced. The time-spectral method is based on the frequency-domain method that reduces the unsteady form of the NS governing equation to the periodic steady state formulation. A powerful adjoint solution method can be effectively integrated into the unsteady design framework for helicopter rotors. The design framework of time-spectral and adjoint-based method can be applied to many areas of the engineering design problems such as wind-turbine blade design and flapping wing MAV design.

  • Dr. Bernd Chudoba
  • The University of Texas at Arlington
  • 118C Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

April 16, 2012 – Abstract:

The motivation for this presentation is best summarized in the words of Brockway McMillan, Undersecretary of the Air Force: "The gap I refer to is the planning gap -- our failure to answer adequately the question I just asked ... we don't spend enough time, energy, or talent in deciding how to deploy our technological resources -- in other words, in deciding what to develop out of the products of our research" (Aerospace Management, Feb. 1964, p. 62).

The development of subsonic to hypersonic aircraft and space vehicles starts with the strategic conceptual design phase. The conceptual design phase itself can be subdivided into three distinct sub-phases: (a) parametric sizing, (b) configuration layout, and (c) configuration evaluation. Of these phases, parametric sizing represents the domain of the strategist and forecaster. This key phase is often misunderstood thus underrepresented due to its abstract nature amongst the multi-disciplinary sciences. This early screening capability identifies the correct design mission thus business case, it is used to develop aerospace infrastructure architectures and technology roadmaps; finally it represents the primary product definition step. This parametric sizing mindset and toolset is employed in propriety future projects environments like Lockheed Martin Skunk Works/ADP, Boeing Phantom Works, Airbus FPO, and others. Since the important strategic and managerial decisions occur early during a project, the quality of the parametric sizing implementation is crucial.

Today, detailed design investigations of aircraft and space vehicles are conveniently performed by the ‘technologist’ with an emphasis on increasing the level of accuracy for a given point-design whilst consuming most of the budget and development time. In contrast, the primary vehicle design decisions during the earlier conceptual design phase are still made by the ‘integrator’, often using over-simplified analyses and heuristics in a short amount of time. Note that the integrator or conceptual designer is responsible for identifying the correct solution-space topography containing candidate point-designs. This presentation introduces the primary elements to be required by any competitive aerospace future projects team focusing on quality decision-making. The resulting 21st century aerospace product development capability delivers multi-disciplinary solution-space topographies to the decision-maker, integrator, and technologist, overall aimed at reducing cost, risk, and development spans.

  • Dr. Pradeep Raj
  • Independent Consultant
  • 310 ICTAS
  • 12:00 noon
  • Faculty Host: Dr. Rakesh Kapania

April 12, 2012 – Computational Fluid Dynamics (CFD) capabilities for flow analysis have evolved from simplified geometry, simplified physics models of the late sixties and early seventies to complex geometry, sophisticated physics models used routinely today. In the early years, some experts unrealistically expected CFD to displace and supplant wind tunnels for producing aerodynamic data for aircraft design—characterized by this author as irrational exuberance. However, even after more than three decades of dramatic advancements, the full potential benefits of CFD elude us; it continues to serve as an able complement to wind tunnels. Our inability to produce credible computational predictions is the primary cause of this predicament—a sobering reality indeed. Going forward, it is essential that we focus our energies on correcting this situation because ability to produce credible data using CFD is the cornerstone of a promising strategy for successfully tackling the affordability challenge: developing technologically superior aircraft at affordable cost.

Simulation Based Design (SBD) offers a promising strategy for tackling the affordability challenge by rectifying the deficiencies of the traditional design practices. The deficiencies can be traced to a heavy reliance on experimental tests to generate data for configuration design and on developing physical prototypes to verify functional and operational characteristics which render the entire development effort too long and too expensive to meet customer expectations. A SBD effort employs integrated multi-disciplinary models, computational simulations, and simulators to guide the development of a virtual prototype (VP) with a degree of functional realism comparable to a physical prototype. The key measure of success is the level of fidelity with which a VP reproduces the characteristics of the real airplane. Clearly, realistic predictions of the requisite characteristics hold the key to success. And generating realistic predictions requires increasingly sophisticated high-fidelity physics-based modeling & simulation methods that exploit the ever increasing power of high-performance computers.

CFD plays a pivotal role in realizing the full potential benefits of SBD. CFD provides aerodynamic forces, moments and stability & control parameters required to assess VP performance to ensure that the final design will be capable of successfully carrying out the intended mission. Also, CFD provides inputs to several other engineering disciplines supporting the design effort. For example, airframe structural design requires steady and unsteady loads that CFD can provide. Flight control system design requires airplane response to control commands, and CFD can provide incremental forces and moments due to control surface deployment. In addition, CFD can provide on- and off-body data for an improved understanding of the flow features which offers valuable guidance for design modifications. It is worth noting that there is one design activity, namely, shape optimization, for which CFD is uniquely suited whereas any experimental testing based approach is totally inadequate. Of course, the key to success is: credible data.

  • Dr. Eric Paterson
  • The Pennsylvania State University
  • 118C Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Roger Simpson

April 9, 2012 – Over the past 10 years at Pennsylvania State University, I have established a diverse and vibrant research program in the fields of naval hydrodynamics, wind and hydro power, chemical trace detection, and cardiovascular devices. There are several common threads woven between these projects which I will expand upon in this talk, including: collaborative team research; complementary experiments, theory, and computer modeling; computational multi-physics and high-performance computing; and the importance of core fluid-dynamics competency. While the discussion will be aimed at the level of a programmatic overview, I will summarize some of the key technical contributions and broader impact of my work. To conclude the seminar, I will discuss academic leadership, the AOE strategic plan, and my vision for the department achieving its goals in education and research associated with atmospheric, ocean, and space vehicles.

  • Dr. James Hubbard
  • University of Maryland
  • 261 Durham Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Roger Simpson

April 5, 2012 – The Morpheus Laboratory at the National Institute of Aerospace has a strategic interest in pursuing a set of critical technologies and feasibility studies that establish a foundation for the future development of a practical organic aircraft. The technologies to be developed address the critical feasibility issues of 1) highly flexible multifunctional morphing structures, 2) vehicle lift generation and control, 3) civil applications for multiple coordinated organic aircraft, and 4) the development of a practical integrated vehicle system.

An organic aircraft, which makes use of biological and evolutionary approaches to flight, has the potential to make many long-envisioned uses for autonomous air vehicles a reality. Within two decades, an organic vehicle may uniquely serve a civil aeronautics market niche by being safe enough, quiet enough, and agile enough to work in close proximity to people and property. It also offers significant potential for flight within extraterrestrial atmospheres, thereby providing a practical means of extensive planetary exploration. The future vehicle is envisioned as shown in the figure. Terrestrial versions would have a wingspan of about four feet.

The organic aircraft would be ecologically neutral, creating no emissions. It will use highly flexible materials that enable the generation of lift and thrust without the need for bearings, linkages, or a separate propulsion system. Its multifunctional materials will improve flight efficiency. Its wings will gather and store energy, serve as an antenna, and host embedded sensors. The wings will generate lift and thrust through complex motions that actively adapt to the environment, guided by evolutionary computer algorithms. The aircraft will be capable of large configuration changes to create a wide flight envelope, from perching and hovering to high-speed tucked-wing dives. It would be intelligent, thereby enabling autonomous operations. Through advanced sensors, many of which would be integral to the multi-function materials used, it would adapt to changes in its health or its environment, offering protection to itself and to those around it if failures occur. It will communicate with a larger system of vehicles and carry out coordinated multi-vehicle missions that are impossible today. Terrestrial missions may include search and rescue, neighborhood security, large-scale atmosphere sampling, and the detailed inspection of large structures.

Dr. Hubbard, Director and Founder of the Morpheus Laboratory, will present an overview of research results from Project Firefly. These results include new smart skin sensors, passive and active wing morphing architectures, advances in state space modeling of flapping wing vehicles for robust. Project Firefly is a flight based program to ultimately develop a solid state ornithopter for civil applications that include search and rescue, atmospheric data collection, wild fire fighting, and crop surveys.

  • Dr. Farhan Gandhi
  • The Pennsylvania State University
  • 4:15 p.m.
  • 118C Surge Building
  • Faculty Host: Dr. Roger Simpson

March 26, 2012 – In this seminar, Prof. Farhan Gandhi will speak on two recent areas of research activity. The first is the area of helicopter rotor morphing, which can result in envelope expansion, performance improvement and increased operational flexibility of the helicopter. In particular research on rotor span morphing, chord extension and twist morphing will be presented, along with discussions on the rationale for the selections and approaches. The second is the area of adaptive cellular structures. Prof. Gandhi's research group has examined both conventional and novel topologies (including zero Poisson's ratio and multi-stable cellular structures) for a wide variety of applications including energy absorption, morphing, and high stiffness and simultaneously high damping.

  • Dr. Dewey H. Hodges
  • Georgia Institute of Technology
  • 261 Durham Hall
  • 4:15 p.m.
  • Faculty Host: Dr. Roger Simpson

March 22, 2012 – In modeling of structures with one dimension significantly larger (or smaller) than the other two, one can reduce the complexity of the resulting analysis by taking advantage of inherent small parameters. This results in reduced-dimensional models, such as beams (or plates/shells), and a much simpler mathematical formulation that helps to save computational costs. With the advent of composites and structural members with initial twist/curvature, particularly in the field of aerospace engineering, using beam, plate or shell theories based on traditional approaches and ideas will not yield accurate results. The variational-asymptotic-method (VAM) provides a mathematically rigorous way to reduce the 3D problem into a 1D beam-like (or 2D plate/shell) but without a priori assumptions such as "plane sections remain plane" or other oversimplifications. In this seminar, an overview of VAM is presented along with a description of how it can be used to develop reduced-order models for beams, plates and shells. The results are verified for test cases by comparisons with 3D solutions or 3D FEM results.

  • Dr. James Tangorra
  • Drexel University
  • 118C Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Michael Philen

Feb. 27, 2012 – Bony fish swim with a level of agility that is unmatched in human-developed underwater systems. This is due, in large part, to the ability of fish to carefully control hydrodynamic forces through the sensory based modulation of the fins' kinematics and mechanical properties. To better understand how fish produce and control forces, biorobotic models of the bluegill sunfish's (Lepomis macrochirus) caudal and pectoral fins, and of the pectoral fin's sensory and control systems have been developed. The designs of these systems were based on detailed analyses of the anatomy, kinematics, and hydrodynamics of the biological fins and on neuromechanical studies of the sensory systems intrinsic to the biological fins. These models have been used to investigate how fin kinematics and mechanical properties influence propulsive forces and to understand how sensory information gathered about the fin and the flow relates to fin performance.

  • Dr. Sang-Eon Chun
  • Samsung Heavy Industries, Ltd.
  • 118C Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Feb. 6, 2012 –

Sloshing remains an issue for LNG (Liquefied Natural Gas) industry, particularly for LNG tankers and FPSO/FSRU, etc., with membrane-type LNG CCS (Cargo Containment System), which use the hull structure as the load bearing tank body and have the relatively soft insulation material between the LNG cargo and the hull structure. The insulation material structure is adopted only to maintain the low temperature inside the tank and to protect the hull structure from being exposed to the critically low temperature. If the baffle plates are introduced to reduce the sloshing motion inside the LNG tanks, it is unavoidable to support them onto the load bearing hull structure, which inevitably leads to heat paths and deteriorates the insulation performance of the LNG CCS. Therefore, the sloshing issues in the membrane-type LNG CCS are partially treated by adopting the octagonal shape to reduce the impact load due to sloshing motion and reinforcing the insulating structures of LNG CCS, which is supposed to be constrained by economic and technical limitations. In spite of these design changes, the sloshing concern relating to possible damages on the CCS is still limiting the operating conditions and so the new business chances; LNG tankers are allowed to operate with the LNG cargo filled more than 80% or less than 10% of the tank height.

In this paper, a unique and innovative solution to the sloshing conundrum, named as ABAS (Anti Boil-off gas Anti Slosh) blanket system, is unveiled, which can dampen the motion of LNG inside the LNG cargo vessels in operation in a cheap and effective way and, as a result, the sloshing loads on CCS can be reduced significantly. This design concept has been proved through various sloshing model tests, which show the dramatic reduction of sloshing motion. Finally, the production of prototypes of floating unit structures which are assembled into a floating blanket layer, ABAS blanket system, shows the applicability in real LNG vessels.

And in conclusion, the speaker will share his own experiences to solve the technical issues based on the Seven Da Vincian principles in the book of How to Think like Leonardo Da Vinci written by Michael Gelb.

  • Dr. Stefan Siegel
  • Atargis Energy Corporation
  • 211 Randolph Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Feb. 1, 2012 – This presentation introduces a novel ocean wave energy converter (WEC), namely, a Cycloidal turbine, as a wave termination device. A Cycloidal turbine employs the same geometry as the well-established Cycloidal or Voith-Schneider Propeller. The main shaft is aligned parallel to the wave crests and fully submerged at a fixed depth. We show that the geometry of the Cycloidal WEC is suitable for single sided wave generation as well as wave termination of straight crested waves using feedback control. The Cycloidal WEC consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft. An experimental and numerical investigation into the wave generation capabilities of the WEC are presented in this paper, along with wave cancellation results for deep water waves. The experiments are conducted in a small 2D wave flume equipped with a flap type wave maker as well as a 1:4 sloped beach. The operation of the Cycloidal WEC both as a wave generator as well as a wave energy converter interacting with a linear Airy wave is demonstrated. The influence that design parameters radius and submergence depth on the performance of the WEC have is shown. For wave cancellation, the incoming wave is reduced in amplitude by ≈ 80%in these experiments. In this case wave termination efficiencies of up to 95% of the incoming wave energy with neglegible harmonic waves generated are achieved by synchronizing the rotational rate and phase of the Cycloidal WEC to the incoming wave.

  • Dr. Guoming (George) Zhu
  • Michigan State University
  • 118C Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Jan. 30, 2012 – The output covariance constraint (OCC) problem will be introduced with both deterministic and stochastic interpretations. A control design algorithm with guaranteed convergence will also be presented with application to the pointing control of the Hubble Space Telescope. Note that with the scalar output covariance constraints, the solution of the OCC problem also provides an optimal control for the constrained H2 problem. Next, the talk will address the output H2 weight tuning for the mixed H2/H∞ LPV (linear parameter variation) control problem for polytopic discrete time LPV systems. By properly selecting the output H2 weighting, multiple performance constraints on the output H2 norms are met while minimizing the H2 control effort. Normally, the output H2 weighting is selected in an ad hoc manner for the mixed H2/H∞ LPV control problem. The iterative algorithm provides a way to find the output H2 weighting such that the designed mixed H2/H∞ LPV controller satisfies the performance constraints. An illustrative example will be presented to demonstrate the effectiveness of the iterative algorithm.

  • Dr. Serge Prudhomme
  • Institute for Computational Engineering and Sciences (ICES)
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Christopher Roy

Dec. 5, 2011 – Finite Element methods are widely used today for the solution of boundary- and initial-value problems of scientific and engineering interest. However, these methods, as with any other numerical methods, only provide approximations of the true solutions, which, therefore, inevitably contain errors due to the discretizations in space and time. In this talk, we will describe in detail adjoint-based techniques for a posteriori estimation and adaptive control of the discretization errors, measured with respect to quantities of interest. These so-called goal-oriented error estimation methods will be illustrated on a series of model examples, ranging from linear elliptic problems to nonlinear and time-dependent problems. We will also show how one can extend these methods to the case of coupled problems and how one can design adaptive methods for optimal control of the discretization error in the quantities of interest.

  • Dr. Geir Dullerud
  • University of Illinois at Urbana-Champaign
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Mazen Farhood

Nov. 14, 2011 – This seminar finds its basis in mathematically grounded questions about collaboration and control in multi-agent dynamical systems. It is inspired from a practical perspective by recent advances in sensing, computing and networking hardware that make reconfigurable multi-agent systems both technologically and economically feasible on a widespread scale. Examples of such systems include satellite formations, consumer robotics, and more generally networked subsystems of mobile sensors and actuators that cooperate to achieve some aggregate functionality. There are many shared design challenges associated with these types of systems, and the talk will focus on two specific issues: (1) switched hybrid dynamics; and (2) network latency and multi-resolution sensing for control. The technical setting for the talk is the framework of convex optimization, and the results presented lead directly to implementable analysis and design algorithms via semidefinite programming. In part of the work presented on switched dynamics, we will as a special case provide an exact solution to a long-studied receding horizon problem, the first exact solution to this problem to our knowledge. A portion of the presentation will be devoted to describing the experimental multi-vehicle testbed, HoTGames, which consists of wirelessly linked miniature hovercraft, quad-rotor helicopters and wheeled vehicles all capable of onboard multi-modal sensing, and interaction with the Internet and a vision-based sensor network.

  • Dr. Matthew Oehlschlaeger
  • Rensselaer Polytechnic Institute
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Lin Ma

Nov. 7, 2011 –

Gas-phase autoignition, the topic of the first half of this seminar, and its underlying reaction kinetics are of fundamental importance to the operation of combustion-based aero-propulsion engines, particularly in advanced engine concepts where kinetics is of greater importance than in legacy designs. The increasing significance of kinetics in modern engine operation and the rapid development of alternative fuels from biomass and other sources motivates a science-based understanding of reaction kinetics and in particular the influence of fuel structure and composition on oxidation and autoignition. The results of shock tube autoignition studies for low volatility conventional and alternative aviation fuels and components under wide-ranging conditions will be discussed. These studies provide: 1) fundamental information about the structure-reactivity relationships for fuels, 2) targets for the development of fuel oxidation kinetic models, 3) assessment of simplified surrogate mixtures designed to mimic the behavior of real fuels and the methodologies used for their formulation, and 4) information that can be used in the design and development of combustors.

In the second half of the seminar exploratory efforts to use the photoignition of nanomaterials dispersed in fuel/oxidizer mixtures to manipulate ignition and combustion wave propagation will be presented. Initial results show that photoignition can be used to achieve quasi-homogenous ignition of gaseous fuel/air/nanomaterial mixtures and reduce flame acceleration and deflagration-to-detonation time and length scales by around a factor of two.

  • Mr. Philip Van Seeters
  • Boeing Commercial Airplanes
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Oct. 17, 2011 – An airplane is the compromise of the reaction to a wealth of requirements and the product of numerous disciplines and systems interacting in unison and harmony. The airplane designer's responsibility is to synthesize all requirements and disciplines to arrive at an integrated solution. Successful design engineers carry a set of fundamental tools which help them understand the impact on the integrated vehicle that result from (changes to) a given system. But like any tool, the tool is only as good as its user. One such tool is the payload-range diagram; it communicates mission capabilities and is sensitive to weight changes, aerodynamic efficiency, and propulsion efficiency. It can be used to tailor a vehicle to a range of missions, and is useful in devising a family plan of aircraft. This seminar will dive into the nuts and bolts of the payload-range diagram and focuses on the application to commercial aircraft.

  • Dr. Luciano Castillo
  • Texas Tech University
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. William Devenport

Oct. 10, 2011 – Although wind turbines have been well studied from a blade aerodynamics perspective, the interactions among these massive structures and the atmospheric turbulent boundary layer (ATBL) are still not understood in detail. It is important to understand such interactions in order to maximize the energy that can be extracted from the available wind resource. Past investigations have determined that wind turbines that operate within an array can display a significant power generation loss, when compared to a freestanding wind turbine. Thus, their ability to extract kinetic energy from the flow decreases due to complex interactions among them, the terrain topography and the atmospheric boundary layer.

In order to improve the understanding of the vertical transport of momentum and kinetic energy across a boundary layer flow with wind turbines, wind-tunnel experiments were performed to include: a single wind turbine blade, a single wind turbine and a scaled down wind array. The boundary layer flow includes a 3 X 3 array of model wind turbines. Particle-image-velocity measurements in a volume surrounding a target wind turbine are used to compute mean velocity and turbulence properties averaged on horizontal planes. The impact of vertical transport of kinetic energy due to turbulence and mean flow correlations is quantified. It is found that the fluxes of kinetic energy associated with the Reynolds shear stresses are of the same order of magnitude as the power extracted by the wind turbines, highlighting the importance of vertical transport of turbulence in the boundary layer and thus in wind farms. Moreover, the streamtube is visualized in a single wind turbine in order to gain insight into the flow and to test the axisymmetric assumption used for the calculation of the induction factor. Results show that the streamtube is indeed close to axisymmetric, but exhibits some slight distortions due to strong tower effects and shear from the wall.

  • Dr. Andrew Sinclair
  • Auburn University
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Troy Henderson

Oct. 3, 2011 – Abstract: TBA

  • Dr. David Poling
  • Deputy Program Manager
  • Joint Multi Role Program, Boeing
  • 1060 Torgersen Hall
  • 7:30 - 8:00 p.m.
  • Sponsored by the AOE Advisory Board with AIAA, ASNE, SNAME, and SGT.

Sept. 29, 2011 – Topic: Boeing Company Overview.

  • Ms. Kristin Swift
  • Principal Deputy Director
  • USN and USMC Airworthiness Directorate at Naval Air Systems Command
  • 1060 Torgersen Hall
  • 7:00 - 7:30 p.m.
  • Sponsored by the AOE Advisory Board with AIAA, ASNE, SNAME, and SGT.

Sept. 29, 2011 – Topic: Women in Military Aviation.

  • Mr. Bob Hanley
  • Director
  • USN and USMC Airworthiness Directorate at Naval Air Systems Command
  • 1060 Torgersen Hall
  • 6:30 - 7:00 p.m.
  • Sponsored by the AOE Advisory Board with AIAA, ASNE, SNAME, and SGT.

Sept. 29, 2011 – Topic: Airworthiness Certification and Initial Fleet Introduction of the F-35 Lighting Joint Strike Fighter.

  • Dr. Umesh Vaidya
  • Iowa State University
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Sept. 26, 2011 – Analysis and control of uncertain nonlinear systems exhibiting non-equilibrium dynamics is of interest in various applications such as fluid flow control, electric power grid, and biological systems. In this talk we present results on the novel ergodic theory-based framework for the analysis and control of non-equilibrium dynamics in uncertain dynamical systems. Our first main result is on the introduction of Lyapunov measure as a new tool for stability verification and stabilization of non-equilibrium dynamics in nonlinear systems. The main contribution of this work is that it provides for a systematic linear programming based solution for the stability verification and stabilization of nonequilibrium dynamics in nonlinear systems. The novel framework is also used to study the problems of stabilization and estimation of nonlinear systems over uncertain channels and interconnections. The main results prove that fundamental limitations arise in the stabilization and estimation of nonlinear systems over uncertain channels, expressed in terms of channel uncertainty and positive Lyapunov exponents of the open loop nonlinear system. The positive Lyapunov exponents capture the global instability of nonlinear systems. Hence our results highlights, for the first time, the important role-played by the global nonequilibrium dynamics in obtaining the limitation results. The framework is extendable to study more general control problems over uncertain networks with nonlinear components dynamics.

  • Mr. Alex Sang
  • Luna Technologies
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Christopher Roy

Sept. 19, 2011 – The ability to make numerous, distributed measurements in a single, standard optical fiber makes fiber-optic sensing a practical and financially attractive alternative to conventional methods. We present a novel technique for high resolution distributed fiber-optic strain and temperature sensing based on measuring spectral shifts in the Rayleigh backscatter along an optical fiber. High-sensitivity Optical Frequency Domain Reflectometry (OFDR) is used to measure the scatter continuously along the fiber with sub-cm spatial resolution. Distributed measurements of strain and temperature in off-the-shelf telecommunications grade fiber are demonstrated for composite cure monitoring, wind turbine defect detection and structural health monitoring, and crack detection in concrete. This presentation will also include a live demonstration of distributed sensing measurement on a test article.

  • Dr. William Whitacre
  • Northrop Grumman
  • 113 McBryde Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Craig Woolsey

Sept. 5, 2011 – Geolocation is the process of using sensor data to develop statistical estimates of a point of interest (POI) on the ground. When using uninhabited aerial vehicles (UAVs) with gimballing cameras, each UAV, based on its position and orientation, points the camera (through a gimballing payload mount inside the UAV) at the POI on the ground. While the aircraft is moving, and the POI is potentially moving, the camera gimbals must adjust their angles such that the POI always remains within the field of view of the camera. The objective of geolocation is then to estimate the position (2D or 3D) of the POI. Complicating this problem are uncertainties in the aircraft position and orientation, gimbal angles, camera specifications and measurements, and disturbances such as turbulence and engine vibrations.

This presentation will cover four important topics for cooperative geolocation:
1. Decentralized estimation algorithm - A decentralized filtering approach is shown for geolocation that provides tracking accuracy and is further scalable with the number of UAVs

2. Decentralized bias estimation - In practice, there are non zero mean errors (biases), which degrade geolocation accuracy. Therefore, a decentralized approach is developed to simultaneously estimate the unknown location of the POI as well as the biases of each UAV.

3. Methods for communication loss and delay - Communication is an important part of a cooperative geolocation mission. However, in practice, communication losses and delays are inevitable. Therefore, a new method for cooperative geolocation in the presence of communication loss, termed the predicted information method, is developed.

4. Orbit optimization - The optimization of periodic orbits for tracking both stationary and moving targets with two uninhabited aerial vehicles is considered. A natural metric that takes into account the fact that the orbits are periodic, is used and three key results are obtained.

Flight tests with the ScanEagle UAV made by Insitu Inc. will be shown to validate each of the algorithms presented.

  • Dr. Mason Peck
  • Cornell University
  • Holden Auditorium
  • 4:00 p.m.

May 9, 2011 – There is untapped potential for transformative spacecraft missions that use very small, agile satellites. This talk considers the mission-performance benefits and systems-engineering challenges of small length scale from the perspective of attitude-dynamics fundamentals. Violet is a 50 kg agile spacecraft with an optical payload being developed by faculty and students in the Space Systems Design Studio at Cornell University. Dr. Peck will describe Violet’s objectives and system architecture as a case study of this principle and will offer some details on its attitude control subsystem. He will also discuss the design and dynamics of very small control-moment gyroscopes (CMGs). As a nanosatellite, Violet exhibits structural dynamics that are much higher in frequency than larger spacecraft with analogous mission objectives. For this reason, among others, the spacecraft’s eight 0.3 Nm / 0.3 Nms CMGs can be used with comparatively high-bandwidth attitude control to provide extraordinary agility of at least 10 deg/sec, 10 deg/sec^2, and 60 deg/sec^3, with the prospect of as much as four times as much depending on the power available. Mission applications include remote sensing, space situational awareness, and in-orbit inspection and repair of other spacecraft. This general principle, exploiting the dynamics of small-scale vehicles, may motivate even smaller spacecraft. Dr. Peck will discuss some future directions for this research that include centimeter-size spacecraft with surprising orbit mechanics.

  • Dr. Rob McDonald
  • California Polytechnic State University
  • 104D Surge Building
  • 10:05 a.m.

May 6, 2011 – Advanced multidisciplinary physics-based design and analysis capabilities are required to pursue the revolutionary vehicle and technology concepts needed to meet the substantial challenges facing the aerospace community. An aircraft’s shape is the natural starting point for physics-based multidisciplinary analysis and optimization. Its outer mold lines and structural layout are the interface between aerodynamics, structures, mass properties, and all the physics that impact a vehicle’s performance.

The decision makers involved in the design of the next generations of air vehicles need the ability to select and vary the level of analysis fidelity to suit the decision being made. Unfortunately, analysis fidelity is often dictated by the available tools. This limitation frequently stems from the underlying geometry representation.

NASA’s Vehicle Sketch Pad (VSP) is a parametric geometry tool which presents the opportunity to dramatically change the way design is performed. Planned research will result in a geometry engine and an integration framework which are significantly more intelligent, more extensible, and more capable that what is available today. These tools will enable multi-fidelity and multi-physics analysis early in the design process when fundamental decisions are made. This improved design modeling capability will lead to better understanding of the advanced technologies and concepts required to meet the challenges facing the aerospace industry.

  • Dr. Mark Costello
  • Georgia Tech
  • 1060 Torgersen Hall
  • 10:05 a.m.

May 4, 2011 – Given the availability of highly capable computers, algorithms, sensors and actuators, there exists a terrific opportunity for innovation in the design of air vehicle configurations and components to solve pressing practical problems. This talk will focus on two such practical problems and potential solutions recently developed by the Costello Research Group at Georgia Tech. The first problem considered is traversing complex man-made or naturally occurring interior spaces over long periods of time. A new micro rotorcraft was created consisting of a caged coaxial rotor system with an inherent low mass center that is controlled with an internal translating mass. The motivation, development, and performance of this vehicle configuration will be detailed. The second problem involves accurately landing an air dropped payload under a parafoil canopy to within meters of an intended ground impact point. Several new longitudinal glide slope control mechanisms have been invented including dynamic rigging of the canopy in flight as well as using canopy bleed air to construct a virtual aerodynamic spoiler. The talk will conclude with a discussion of the key elements of air vehicle design in the university environment.

  • Dr. James Cutler
  • University of Michigan
  • Holden Auditorium
  • 4:00 p.m.

May 2, 2011 – Nanosatellites are proving to be a useful tool for increasing our capabilities in space flight, space exploration, and space science. For example, at the University of Michigan, we have recently built and launched the National Science Foundation's (NSF) first nanosatellite mission, the Radio Aurora Explorer. RAX is the first of seven missions funded by the NSF to explore space weather through novel experiments and space missions. RAX is a bistatic radar mission to measure ionospheric disturbances at polar latitudes. In this talk, we will discuss the several nanosatellite missions under development at the University of Michigan. Our first mission, RAX, was launched in November 2010 and demonstrated successful bistatic radar measurements. We will also describe our research program focused on design and operation optimization of nanosatellite missions.

  • Dr. Lin Ma
  • Clemson University
  • 1060 Torgersen Hall
  • 10:05 a.m.

April 25, 2011 – The study of modern propulsion systems calls for innovative and effective experimental methods. This talk describes our efforts to develop such methods and apply them to study modern propulsion devices. A suite of advanced laser diagnostics has been developed to address the experimental challenges posed by modern propulsion systems, including the extreme temperature and pressure, highly transient physiochemical processes, control and stability issues, and multi-phase environment. This talk focuses on three topics to illustrate the unique opportunities enabled by these diagnostics for propulsion research: 1) the study of the control and stability of propulsion devices using absorption spectroscopy, 2) the study of dense fuel sprays using ballistic imaging, and 3) the study of fundamental turbulent combustion using particle image velocimetry and photodissociation spectroscopy. The applications of these topics in other cross-disciplinary areas will also be discussed.

  • Dr. Jack Edwards
  • North Carolina State University
  • 1060 Torgersen Hall
  • 10:05 a.m.

April 18, 2011 – The design and analysis of high-speed aeropropulsion concepts requires a fundamental accounting of unsteady flow behavior as induced by shock / viscous layer interactions, fuel injection and mixing, and combustion dynamics. This talk will discuss the development of several computational fluid dynamics techniques and modeling strategies suitable for high-fidelity analyses of such effects, both at a component level and as part of a ‘tip-to-tail’ simulation strategy. These include large-eddy / Reynolds-averaged Navier-Stokes simulation methods for wall-bounded turbulent flows in configurations influenced by multiple solid surfaces, phase-interface capturing techniques for simulating primary atomization, phase-transition modeling for supercritical fuels injection, and immersed-boundary methods for rendering of complicated, possibly moving, objects. Examples pertinent to compressible, reactive flows encountered in aero-propulsion systems will be presented, and future directions for research in this scope will be outlined.

  • Dr. Liangyu Wang
  • United Technologies Research Center
  • 1060 Torgersen Hall
  • 10:05 a.m.

April 11, 2011 – The need for predictive simulations of turbulent combustion becomes more and more urgent in practical device design and performance evaluation. In order to achieve predictive simulations, a range of involved physical and chemical phenomena must be taken into account. These phenomena include turbulent transport, finite-rate chemistry, multiphase flow, soot, thermal radiation, and combustion instability and dynamics. Furthermore, the nonlinear interactions among these physical and chemical processes, such as turbulence-chemistry-radiation interactions, must be modeled properly as well. In the first part of this talk various modeling issues in aeroengine combustor simulations will be discussed. As new combustor technologies emphasize on lean premixed combustion to meet more and more stringent emission regulations, modeling and simulations of liquid fuel injection, fuel air mixing in strong turbulent swirling flows, unsteady heat release, and thermal radiation become critical in the design, evaluation, and optimization of new combustor concepts. Research that has been done and recent development in these areas will be described. In the second part of this talk a recent study on the interactions of water mist with fire radiation will be described in detail. Next generation water mist systems are being developed to compete with multi-billion dollar sprinkler industry and to extend to residential markets. Thermal radiation affects vaporization rate of water mist and, therefore, the penetration and transport of water mist. Water mist and water vapor block radiation transfer to the surrounding walls and combustible materials and, therefore, suppress fire growth and spreading. Results from studying a canonical problem are discussed and key physics are identified for the interactions between fire radiations and water mist.

  • Dr. Chi Yang
  • George Mason University
  • Holden Auditorium
  • 4:00 p.m.

April 4, 2011 – With the rapid development of computer hardware and software, large-scale computational simulations are making significant contributions to many important areas of ship hydrodynamics. Computational Fluid Dynamics (CFD) in particular is proving to
be extremely useful in the hydrodynamic analysis and design of ships. The future of the CFD in ship hydrodynamics is to improve available CFD tools and integrate them in a comprehensive simulation environment to predict and study ship behaviors at sea and perform hydrodynamic design optimization of ship hulls.

An integrated graphic user interface (GUI) toolkit for ship hydrodynamic analysis and hull form optimization has been developed. The main components of this toolkit consist of a practical design-oriented simple CFD tool and an advanced CFD tool; a hull surface representation and modification module; and an optimization module. The simple CFD
tool can be used for the preliminary and early stages of the hydrodynamic design of hulls, and the advanced CFD tool for the detailed flow analysis at late stages of the hydrodynamic design of hulls. Both the simple CFD tool and the advanced CFD tool have been improved and further validated. New hull surface representation and modification techniques have been developed to allow both local and global modifications of the hull form with any given constraints during the hydrodynamic
optimization process. It can also be used to conduct parametric studies of the hull hydrodynamic performances. In addition, the new hull surface modification technique can be used to generate an initial hull form to satisfy the design needs first before
performing the optimization. Various optimization techniques are implemented in the optimization module to satisfy different optimization requirements. An overview of the recent advances in both the simple CFD tool and the advanced CFD tool, and the application of the toolkit to both single and multi-objective hydrodynamic optimization problems will be presented. The first version of the ship design and hull form optimization software will be introduced. This software can be further developed and enhanced, so that it can be used not only by naval architects for routine hull form design and hydrodynamic analysis, but also for the education of future naval architects.

  • Dr. Adam Steinberg
  • German Aerospace Center (DLR) Institute of Combustion Technology
  • 1010 Torgersen Hall
  • 10:05 a.m.

April 4, 2011 – The past several years have seen a great increase in gas turbine engine deployments, along with a concurrent demand for drastically reduced pollutant emissions. Effectively meeting these increasingly stringent emission targets has been hampered by the tendency of low-emission engines to exhibit self-excited and self-destructive thermo-acoustic instabilities. Such instabilities are driven by a complex flow-combustion-acoustic coupling, the prediction of which is not yet possible. Control schemes are therefore applied as a redesign or retrofit when unstable conditions are encountered in late-stage testing of new engines, at a great expense of time and money. Furthermore, since the instabilities are not fundamentally solved, they have a tendency to reappear when minor design upgrades or changes in fuel composition are made. However, our understanding and management of thermo-acoustic instabilities can be greatly aided by recent advances in high-repetition-rate laser-based flow and combustion diagnostics. This seminar will discuss a current research program that uses a suite of such diagnostics to better understand and predict how thermo-acoustic instabilities are excited in low-emission gas turbine combustors. A detailed analysis of the flow-combustion-acoustic coupling will be presented for a variety of swirl-stabilized flames. Due to the temporal resolution afforded by the diagnostics, quantification of previously unobserved and thermo-acoustically coupled flow-flame interaction dynamics is possible. Furthermore, by simultaneously resolving multiple periodic processes, the high-speed measurements provide a three-dimensional map of how energy is transferred between heat release and acoustic oscillations through such interactions. The understanding of thermo-acoustic energy transfer gained from this analysis has the potential not only to aid in avoiding unstable states, but to allow tailoring of combustors such that natural flow features provide an effective means of damping instabilities.

  • Dr. Ratneshwar Jha
  • Clarkson University
  • 1060 Torgersen Hall
  • 10:05 a.m.

March 23, 2011 – This presentation will focus on the technologies of smart structures and adaptive systems with applications to aircraft design. Smart structures technology has the potential to significantly impact numerous products in diverse industries such as aerospace, wind energy, and civil infrastructure. Recent research in the Smart Structures Laboratory at Clarkson University will be presented with particular emphasis on Lamb wave based health monitoring of aerospace composite structures. This research involves the development of damage detection algorithms through an understanding of structural mechanics, elastic wave propagation, and advanced signal processing. The use of wavelet based spectral finite elements (FE in frequency domain) for wave propagation in composite plates will be discussed. An overview of vibration based damage detection using proper orthogonal decomposition and Hilbert-Huang transform will be presented.

Adaptive control systems can maintain consistent performance of a system in the presence of uncertainty or unknown variation in plant parameters. A hybrid adaptive control scheme is designed as a launch vehicle flight controller for ascent phase of NASA Crew Launch Vehicle. The hybrid adaptive control approach augments linear feedback signals with contributions from both direct and indirect adaptive control elements. In addition, signal filters are incorporated into the feedback loop to prevent harmful interaction between the flight control system and structural bending modes. The performance of the hybrid adaptive flight controller is compared to that of a typical gain-scheduled linear feedback controller in a high-fidelity Ares I ascent simulator obtained from the NASA Marshall Space Flight Center. The hybrid controller shows superior performance compared to a traditional PID flight controller for both rigid and flexible cases. Applications of adaptive control for active vibration suppression and flow control will also be discussed briefly.

  • Ms. Lauren Hunt
  • Texas A&M University
  • Holden Auditorium
  • 4:00 p.m.

March 21, 2011 – Laminar Flow Control (LFC) techniques are used in air-vehicle design to delay the onset of boundary-layer transition, ultimately reducing fuel burn and improving aircraft efficiency. Delaying transition on a swept wing dominated by a
crossflow instability through the use of spanwise-periodic discrete roughness elements (DRE) has been successfully demonstrated both in ground and flight tests. However, the DRE effectiveness appears much more limited under flight conditions. The reason for the difference between wind tunnel and flight tests is not well understood, but a recently reactivated ground test capability may begin to explain these differences.

The low-disturbance Klebanoff-Saric Wind Tunnel was relocated from Arizona State University (ASU) to Texas A&M University (TAMU) in 2005. During its subsequent reconstruction, several component modifications were introduced to further enhance flow quality and experimental control. This talk discusses the changes made to the tunnel and the resulting flow-quality measurements. Final turbulence levels are compared to the ASU flow quality and the significance of these results is discussed in the context of an on-going crossflow instability experiment at TAMU using the ASU model. New stability and receptivity data and their implications for ongoing flight and wind tunnel tests are presented.

Acknowledgement: This work was supported by the NASA Aeronautics Scholarship Program and AFOSR Grant FA9550-08-1-0093.

  • Dr. Timothy Takahashi
  • Santa Clara University
  • 1060 Torgersen Hall
  • 10:05 a.m.

March 21, 2011 – This seminar will discuss several technology and design issues that impact the design of future commercial aviation, as well as military transport, strike, and combat aircraft. It will discuss:


1. How visualization of mission performance parameters as "point-performance" reveals how the actual, realizable performance of an airframe may be substantially lower than that implied by its peak aerodynamic efficiency, L/D.
2. How propulsion system loads and losses (that affect thrust levels) may have unintended consequences upon mission performance.
3. How using a true mission performance code (not Breguet’s equation) coupled to an aerodynamic thickness allocation scheme coupled to a medium-fidelity structural weight prediction scheme to perform a multi-disciplinary study reveals that the most aerodynamically favorable designs have the best system performance.

  • Dr. David Finkleman
  • Center for Space Standards and Innovation
  • Holden Auditorium
  • 4:00 p.m.

March 14, 2011 – This talk examines diverse approaches to representing gasdynamic drag effects on Low Earth Orbit (LEO) satellites. Although the total drag force on a satellite can be measured, the physics of gasdynamic resistance, dynamics of the orbiting body, and characteristics of the atmosphere are inextricably combined. Investigators must hypothesize physical relationships among the drag force, body shape, size, and orientation, the distribution of density, and the predictive assessment of density. Drag coefficients determined under one set of hypotheses are often employed improperly in orbital assessments that use a different set of hypotheses. Our goal is to consolidate the existing information, establish a framework for future research, and expose practical issues.

  • Dr. Robert Niewoehner
  • United States Naval Academy
  • 1010 Torgersen Hall
  • 10:00 a.m.

March 14, 2011 – Dr. Niewoehner’s first flight during the F/A-18 E/F’s development exposed a nightmare. Further testing revealed a strong transonic abrupt wing stall (“wing drop”) which nearly caused the technical collapse of the Super Hornet as a program.
Embarrassingly, the wind tunnel develop had provided advance clues, yet clues that no one in government or industry were prepared to properly interpret. Had those clues been seen by engineers of the 1950s, the problem would have been diagnosed long before first flight; the challenge was not new, but forgotten. A two-year effort, flown principally by Dr. Niewoehner, devised an imperfect fix. The airplane was fielded on time, and won laurels in battle, yet two questions remained. “Can we find a better fix?” “Can we avoid being surprised by this again?” A Navy/NASA/Industry effort was
funded by the Joint Strike Fighter office to better understand the phenomenology, including its historical impacts, and then develop diagnostics for mitigating the challenge in future designs. The F-35C now sports spoilers on its outboard wing panels
mitigating the risk of its appearance in that program’s design. This presentation will recount the history, findings, and applications of the study group’s work.

  • Dr Rajkumar Pant
  • Virginia Polytechnic Institute and State University
  • Holden Auditorium
  • 4:00 p.m.

Feb. 28, 2011 – Travelers on short haul routes demonstrate some very interesting trade-offs. Most passengers tend to prefer the mode that offers them the lowest Generalized Cost of travel (GCT), which represents the sum total of all the direct and indirect costs incurred. This talk will discuss a methodology for conceptual design and optimisation of twin-turboprop aircraft for short-haul business travel. GCT is considered to be the summation of costs related to the access to and from the airport (Access Cost), provision of the flight services (Flight Cost), money value of the total travel time (Time Cost), and costs associated with setting up and operating the airport (Airport Cost). An aircraft conceptual design and optimization problem is posed in terms of 17 design variables and nine constraints. The methodology obtains the configuration and flight profile of the aircraft and the associated airport infrastructure that meets the expected level of travel demand at the least possible GCT. The methodology can also be utilised to carry out a comparative analysis of the GCT of competing Commuter and Regional aircraft, to assess their suitability of operation over a particular route. As a demonstration of the application of this methodology, the results of two case studies for short-haul business air-travel in India are presented. These case studies illustrate the efficacy of this methodology for a systems-engineering based planning and analysis of an air transportation system.

  • Dr. Umesh Vaidya
  • Iowa State University
  • Holden Auditorium
  • 4:00 p.m.

Feb. 7, 2011 – Analysis and control of uncertain nonlinear systems exhibiting non-equilibrium dynamics is of interest in various applications such as fluid flow control, control of complex networks, and biological systems. In this talk we present
results on the novel ergodic theory-based framework for the analysis and control of non-equilibrium dynamics in uncertain dynamical systems. Our first main result is on the introduction of Lyapunov measure as a new tool for stability verification and stabilization of non-equilibrium dynamics in nonlinear systems. The main contribution of this work is that it provides for a systematic linear programming based solution for the stability verification and stabilization of non-equilibrium dynamics in nonlinear systems. The novel framework is also used to study the problems of stabilization and estimation of nonlinear systems over uncertain channels and interconnections. We show that fundamental limitations arise in the stabilization and estimation of nonlinear systems over uncertain channels, expressed in terms of variance of channel uncertainty and system instability. The main contribution of this work is that it highlights, for the first time, the important role-played by the global non-equilibrium dynamics in obtaining the limitation results. The framework is extendable to study more general control problems over uncertain networks with nonlinear components dynamics.

  • Dr. Francis Aviles Cetina
  • Centro de Investigacion Cientifica de Yucatan (CICY)
  • Holden Auditorium
  • 4:00 p.m.

Jan. 24, 2011 – This talk will discuss the use of multiwalled (MW) carbon nanotubes (CNTs) as elements for sensing strain and matrix damage in MWCNT-polymer composites. Experimental results will be discussed to demonstrate the high sensitivity to strain and damage of a percolating CNT network, once this has been formed inside the polymer matrix. Specific results of two material systems will be discussed, one that employs a thermoplastic matrix in thin film geometry, and a second one which employs a bulk thermosetting matrix. In addition, this talk will discuss the influence of multi-walled carbon nanotube (MWCNT) alignment into a polymer matrix on the electrical and piezoresistive properties of the resulting composites. An alternating current electric field is employed for MWCNT alignment, which is macroscopically evident in the crystallized polymer. Electrical conductivity and electromechanical sensitivity were improved in the direction of the aligned network. CNT/polymer composites were also tested under loading-unloading cycles, presenting good strain-sensing capabilities.

  • Dr. Greg Young
  • Naval Surface Warfare Center
  • Faculty Host: Dr. Joseph Schetz
  • Holden Auditorium

April 26, 2010 – Aluminum hydride, or Alane, is an interesting material for a wide variety of applications ranging from a hydrogen storage medium for use in automobiles to a fuel supplement in explosives, fuels, and propellants. Alane is particularly interesting as an ingredient in fuels and propellants in propulsion systems, because of its ability to substantially increase the performance of a given system. For instance, thermochemical calculations using the NASA CEA chemical equilibrium code indicate that replacement of aluminum with alane in a typical composite solid rocket propellant (Ammonium Perchlorate/HTPB/Aluminum) increases the specific impulse (Isp) by ~7-8% while also substantially reducing the adiabatic flame temperature. This type of increase in specific impulse can provide large gains in vehicle range as well as significantly decrease the cost of launching a payload into space. For these reasons, alane has been a fuel of great interest since the 1960’s. While it is an extremely attractive material it’s high cost, limited availability, and thermal stability issues have minimized its use. Thus, relatively little information is available on alane in terms of combustion and propulsion behavior. Recently, interest has been renewed in aluminum hydride, sparking a series of studies providing researchers with a rich new area of exploration.