Airfoil-Turbulence Interaction Noise Source Identification and Reduction by Leading-Edge Serrations

The present work is aimed at assessing leading-edge serrations as an airfoil turbulenceimpingement noise (TIN) reduction mean. It relies on extended anechoic wind-tunnel testing including far-field measurements over an observation sphere to infer the three-dimensional features of TIN, and on microphone-array measurements to extract leading-edge noise in frequency. In particular this allows measuring unambiguously reductions of up to 15 dB achieved by serrations on flat plates. A preliminary study of the three-dimensional flow field around the leading edge using time-resolved tomographic particle image velocimetry (PIV) is detailed