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Recent Advances in Wind Turbine Noise Research
Open AccessArticle

Experimental Study of Airfoil Leading Edge Combs for Turbulence Interaction Noise Reduction

1
Technical Acoustics Group, Brandenburg University of Technology Cottbus—Senftenberg, 03046 Cottbus, Germany
2
Department of Engineering Science, University of Auckland, Auckland 1142, New Zealand
3
Institute of Fluid Mechanics and Engineering Acoustics, Technical University Berlin, 10587 Berlin, Germany
*
Author to whom correspondence should be addressed.
Acoustics 2020, 2(2), 207-223; https://doi.org/10.3390/acoustics2020014
Received: 5 December 2019 / Revised: 25 February 2020 / Accepted: 16 March 2020 / Published: 1 April 2020
The interaction of a turbulent flow with the leading edge of a blade is a main noise source mechanism for fans and wind turbines. Motivated by the silent flight of owls, the present paper describes an experimental study performed to explore the noise-reducing effect of comb-like extensions, which are fixed to the leading edge of a low-speed airfoil. The measurements took place in an aeroacoustic wind tunnel using the microphone array technique, while the aerodynamic performance of the modified airfoils was captured simultaneously. It was found that the comb structures lead to a noise reduction at low frequencies, while the noise at high frequencies slightly increases. The most likely reasons for this frequency shift are that the teeth of the combs break up large incoming turbulent eddies into smaller ones or that they shift turbulent eddies away from the airfoil surface, thereby reducing pressure fluctuations acting on the airfoil. The aerodynamic performance does not change significantly. View Full-Text
Keywords: wind turbine; leading edge noise; turbulence interaction noise; comb wind turbine; leading edge noise; turbulence interaction noise; comb
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MDPI and ACS Style

Geyer, T.F.; Wasala, S.H.; Sarradj, E. Experimental Study of Airfoil Leading Edge Combs for Turbulence Interaction Noise Reduction. Acoustics 2020, 2, 207-223.

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