February 1, 2023: Nathaniel Wei

February 1, 2023
1:30 p.m.
Room: 310 Kelly Hall
Nathaniel Wei, Aeronautics at Caltech
Faculty Host: Dr. William Devenport

"Wind-Turbine Aerodynamics in Unsteady Flow Environments"

Abstract:  Wind energy is poised to play a considerable role in the global transition to clean-energy technologies within the next few decades. Modern wind turbines, like aircraft and other aerodynamic structures, are typically designed with the assumption that the flows they encounter will be uniform and steady. However, atmospheric flows are highly unsteady, and systems operating within them must contend with gust disturbances that can lead to performance losses and structural damage. Thus, the next generation of wind-energy systems requires physics-informed design principles that effectively account for and even leverage these unsteady flow phenomena for enhanced power generation, robustness, and operational longevity. In this talk, we highlight several analytical tools that parameterize unsteady aerodynamics in various wind-turbine contexts. First, two-dimensional models for the lift on airfoils in gusts are shown to be effective in capturing trends from experiments and large-eddy simulations. Second, analytical models for the power production of and flow around a periodically surging wind turbine are validated against experiments, which suggest that floating offshore wind turbines could leverage unsteady surge motions for power-production gains of up to 6% over the stationary case. Finally, field measurements in the wakes of full-scale vertical-axis wind turbines using artificial snow as tracer particles yield insights into the contributions of unsteady vortex dynamics to the performance of turbines in wind-farm arrays. These investigations provide the analytical and experimental foundations for future studies of unsteady atmospheric flows, which will lead to the development of principles and techniques for wind-farm siting, control, and optimization.

Bio: Nathan Wei is a Ph.D. candidate in Aeronautics at Caltech, advised by Prof. John O. Dabiri. His research combines theoretical, experimental, and numerical approaches to characterize the effects of unsteady flows on natural and engineering systems, such as wind turbines, aircraft, and flying and swimming animals. Nathan graduated summa cum laude from Princeton University in 2017 with a B.S.E. in Mechanical and Aerospace Engineering, spent a year at the TU Darmstadt on a Fulbright research fellowship, and earned an M.S. in Mechanical Engineering from Stanford  University in 2020 before moving with his advisor to Caltech. He is the recipient of several fellowships and awards, including a Stanford Graduate Fellowship and National Science Foundation Graduate Research Fellowship.