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Bioinspired trailing-edge noise control

Accepted version
Peer-reviewed

Type

Article

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Authors

Clark, IA 
Alexander, WN 
Devenport, W 
Glegg, S 
Jaworski, JW 

Abstract

Strategies for trailing edge noise control have been inspired by the downy canopy that covers the surface of exposed flight feathers of many owl species. Previous wind tunnel measurements demonstrate that canopies of similar characteristics can reduce pressure fluctuations on the underlying surface by as much as 30dB, and significantly attenuate roughness noise generated by that surface. In the present work, surface treatments are designed to replicate the effects of the canopy in a form suitable for application to an airfoil. These treatments are installed directly upstream of the trailing edge to modify the boundary layer turbulence prior to acoustic scattering by the edge. Over 20 variants of these designs have been tested by performing aeroacoustic wind tunnel measurements on a tripped DU96-W180 airfoil at chord Reynolds numbers of up to 3 million. Compared to the unmodified airfoil, the treatments provided up to 10dB of broadband attenuation of trailing edge noise. The effectiveness of the treatment is not highly dependent on a particular geometry, but there appears to be strong potential for optimization. The surface treatments remain effective over an angle of attack range that extends over 9 degrees from zero lift. Aerodynamic impact of the treatment appears minimal.

Description

Keywords

Journal Title

AIAA Journal

Conference Name

Journal ISSN

0001-1452
1533-385X

Volume Title

55

Publisher

American Institute of Aeronautics and Astronautics (AIAA)
Sponsorship
Office of Naval Research (ONR) (N62909-12-1-7116)
Office of Naval Research (Grant IDs: N00014-13-1-0244, N00014-14-1-0242, N62909-12-1-7116 (NICOP)), College of Engineering at Virginia Tech, AVEC Incorporated