Forced acoustical response of an open cavity coupled with a semi-infinite space

TL;DR

This study develops a modal expansion approach based on coupled mode theory to accurately analyze the forced acoustical response of open cavities coupled with semi-infinite spaces, simplifying the response calculation.

Contribution

It introduces a frequency-dependent eigenmode expansion for open cavity acoustics, reducing basis function ambiguity and improving response prediction accuracy.

Findings

Modal expansion converges with few eigenmodes in relevant frequency range.

Eigenmodes derived from cavity and semi-infinite space coupling.

Method simplifies response calculation for open cavities.

Abstract

This paper presents a study of the forced acoustical response of an open cavity from the perspective of modal expansion. Based on the coupled mode theory, it is shown that the sound pressure distribution of an open cavity excited by a point source placed within the cavity can be expanded by a set of frequency-dependent eigenmodes, which are derived from the coupling between the cavity and a semi-infinite space. The calculation of the acoustical responses for baffled and unbaffled open cavities indicates that the proposed modal expansion converges with only a few frequency-dependent eigenmodes in the frequency range of interest. The results of this study eliminate the ambiguity involving the selection of appropriate basis functions, in modal expansion for the forced response problem in open cavities.