Enhancing Aeroacoustic Wind Tunnel Studies through Massive Channel Upscaling with MEMS Microphones

TL;DR

This paper introduces a large, modular MEMS microphone array for wind tunnel aeroacoustic studies, enabling high-resolution source localization and directivity analysis with scalable aperture sizes.

Contribution

It presents a novel large-scale, modular MEMS microphone array design that allows flexible, synchronized measurements for wind tunnel aeroacoustic research.

Findings

Successful deployment on a wind tunnel model demonstrating source localization.

Enhanced beamforming capabilities with minimized sidelobes.

Validation of source directivity using additional far-field microphones.

Abstract

This paper presents a large 6~m x 3~m aperture 7200 MEMS microphone array. The array is designed so that sub-arrays with optimized point spread functions can be used for beamforming and thus, enable the research of source directivity in wind tunnel facilities. The total array consists of modular 800 microphone panels, each consisting of four unique PCB board designs. This modular architecture allows for the time-synchronized measurement of an arbitrary number of panels and thus, aperture size and total number of sensors. The panels can be installed without a gap so that the array's microphone pattern avoids high sidelobes in the point spread function. The array's capabilities are evaluated on a 1:9.5 airframe half model in an open wind tunnel at DNW-NWB. The total source emission is quantified and the directivity is evaluated with beamforming. Additional far-field microphones are employed to validate the results.