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March 25, 2019: Reducing Airfoil Noise with Leading-Edge Serrations

  • March 25, 2019
  • 4:00 p.m.
  • 100 Hancock Hall
  • Dr. Lorna Ayton, Cambridge University
  • Faculty Host: Dr. William Devenport

Abstract: A dominant source of broadband aeroengine noise arises when the unsteady wakes shed from rotors interact with downstream stators. This so-called leading-edge noise cannot be eliminated, but it can be reduced. By altering the spanwise geometry of the leading edge of an airfoil it is known through experimental testing that leading-edge noise can be significantly reduced over broadband frequencies. In recent years, a multitude of different shapes have been tested and all are seen to have benefits for different frequency ranges, which may be ideal for the reduction of tonal noise, but the question remains; which design is optimal for broadband noise reduction?

This talk presents a theoretical model for leading-edge noise, both for
straight edges and serrated edges. Through theoretical optimisation, a set of rules are proposed which lead to an optimal design for broadband
leading-edge noise reduction. Experimental data on sample new designs validates the theoretical predictions and illustrates up to an additional 7dB noise reduction verses conventional serrated designs.