Experimental study of the aerodynamic noise produced by flow-body interaction by synchronous PIV and microphone array measurements
Résumé
The noise production of an air flow over a NACA 0012airfoil is studied in an anechoic wind tunnel, especially theproduction of tonal noise at the trailing edge. The gen-eral goal of the study is to analyze jointly the velocity fieldalong the spanwise direction and the acoustic far field. Inthis purpose, the velocity field is measured by using theTime-Resolved PIV technique (Particle Image Velocimetryat sampling frequency 20 kHz), while the radiated acousticfield is measured by a microphone array. The acoustic dataare processed by using the beamforming technique, in thefrequency domain. In the configuration studied here, theflow speed is set to 40m/s and the incidence of the airfoilisα=8° (parameters are chosen to generate tonal noise).The main result presented is the spatial distribution of theaeroacoustic sources in the spanwise direction. When mul-tiple peaks are present in the acoustic far field spectrum,the beamforming analysis links each peak with a differentsource area along the trailing edge. This observation is co-herent with a spectrum analysis of the PIV velocity field.
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