Energy exchange in uncorrelated ray fields of vibroacoustics

Abstract

This paper is concerned with the basic equations governing energy and intensity in incoherent ray fields. Some fictitious sources are distributed on the boundary of the domain but also on diffracting wedges and peaks. Their powers are determined by some appropriate boundary integral equations. Once these powers are known, energy and intensity inside the domain are given by a simple superposition of contributions of these sources. All paths of propagation are taken into account including direct, reflected, refracted, transmitted, and diffracted rays, but also, radiation by surface, edge or corner modes, and the reciprocal paths for structural response. This theory unifies several fields from the “radiosity method” in room acoustics which determines the reverberation time to the “radiative transfer method” in structural dynamics which gives the repartition of vibrational energy inside subsystems of built-up structures. This is therefore a candidate for an alternative to statistical energy analysis when fields are nondiffuse.