LOCALIZATION OF SOUND SOURCES BASED ON NEAR FIELD PRESSURE

Abstract

Recently a fundamentally new approach to localization of noise generated by a turbulent flow over a surface was introduced. This approach is based on the hypothesis that reflection of an incident pressure field on a surface does not lead to sound. This approach filters near field data by means of a diffraction filter formulated via the FW-H/Kirchhoff equation. The filtered quantity contains all the acoustically relevant surface pressure, while being orders of magnitude smaller than the hydrodynamic pressure. Although it was only shown for high-fidelity near field data provided by a scale resolved CFD calculation, this approach is not fundamentally limited to highly resolved data. Considering recent trends in development of MEMS-based pressure sensors, surfaces may be densely covered with thousands of these and provide near field data. Because this approach is not limited to acoustic wavelengths, it can extend conventional beamforming techniques in the context of sound source localization. This study investigates the applicability of this approach based on near field data provided by a surface covered with said MEMS. For this, an airfoil subject to a circular jet stream is considered