Modelling the pressure field in the vicinity of a microphone membrane using PIV

TL;DR

This paper introduces a non-intrusive method to estimate the acoustic pressure near a microphone by measuring particle velocity with PIV and applying a Green function-based model, revealing diffraction effects.

Contribution

The paper presents a novel approach combining PIV measurements and Green function modeling to estimate near-field acoustic pressure around microphones.

Findings

Diffraction causes about 0.1 dB increase in pressure at microphone edges.

The method accurately estimates pressure using particle velocity data.

Green function-based model effectively predicts pressure distribution.

Abstract

A new approach for for estimating the acoustic pressure in the near field of a microphone based on non-intrusive direct measurement of acoustic particle velocity is proposed. This method enables the estimation of the acoustic pressure inside a domain located in front of the microphone membrane. The acoustic pressure is calculated using the acoustic particle velocity on the frontiers of this domain and a physical model based on the Green function of the system. Results are obtained using the acoustic velocity measured with Particle Image Velocimetry (PIV) in front of a microphone excited with a plane wave inside a rectangular waveguide. They show that the diffraction of the plane wave by the microphone leads to an increase of the acoustic pressure on the microphone edge in the order of magnitude of 0.1 dB.