Homogeneous porous materials like rock wool or synthetic foam are the main tool for acoustic absorption. The conventional absorbing structure for sound-prooﬁng consists of one or multiple absorbers placed in front of a rigid wall, with or without air-gaps in between. Various models exist to describe these so called multi-layered acoustic systems mathematically for incoming plane waves. However, there is no eﬃcient method to calculate the sound ﬁeld in a half space above a multi layered acoustic system for an incoming spherical wave. In this work, an axi-symmetric multi-domain boundary element method (BEM) for absorbing multi layered acoustic systems and incoming spherical waves is introduced. In the proposed BEM formulation, a complex wave number is used to model absorbing materials as a ﬂuid and a coordinate transformation is introduced which simpliﬁes singular integrals of the conventional BEM to non-singular radial and angular integrals. The radial and angular part are integrated analytically and numerically, respectively. The output of the method can be interpreted as a numerical half space Green´s function for grounds consisting of layered materials.
|Seiten (von - bis)
|Journal of Computational Physics
|Veröffentlicht - 2017
- Nicht definiert
- Computational acoustics Boundary element method Absorption