Influence of edge diffraction on thein situmeasurement of impedanceusing microphone arrays

Efren Fernandez Grande, Eric Brandão

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

When measuring the surface impedance and/or the sound absorption coefficient of a material sample in situ, one of the main concerns is the sample size effect due to edge diffraction. In recent years, several in situ impedance measurement techniques using arrays of microphones have been proposed. This paper aims at analysing the the effect of edge diffraction on the in situ measurement with arrays of microphones based on a numerical simulation framework. A simplified Boundary Element Method (BEM) is used to emulate the measurement performed by two types of arrays: (i) - a double layer array, consisting of two parallel layers of uniformly spaced microphones; (ii) - a three-dimensional randomized array, consisting of an irregular distribution of measurement points within a parallelepiped. The study examines different array configurations (size and number of sensors) and sample properties (size and absorption). The wave-number spectrum is used to examine the effect of edge diffraction. The influence of
edges on the estimation of surface impedance and the absorption coefficient is also analysed and compared to the estimation made with a single pressure-velocity probe.
Original languageEnglish
Title of host publicationProceedings of Inter-Noise 2020
Number of pages12
Publication date2020
Publication statusPublished - 2020
Event49th International Congress and Exposition on Noise Control Engineering - Virtual event
Duration: 23 Aug 202026 Aug 2020
https://internoise2020.org/

Conference

Conference49th International Congress and Exposition on Noise Control Engineering
LocationVirtual event
Period23/08/202026/08/2020
Internet address

Fingerprint Dive into the research topics of 'Influence of edge diffraction on thein situmeasurement of impedanceusing microphone arrays'. Together they form a unique fingerprint.

Cite this