3D acoustic simulation inside closed rooms bounded by non-parallel floor and ceiling surfaces

Abstract

A model for the simulation of the three-dimensional (3D) sound pressure level generated by acoustic sources inside closed rooms bounded by non-parallel floor and ceiling surfaces is presented. The 3D problem is solved as a sequence of two-dimensional (2D) problems with different spatial wavenumbers kz, after a spatial Fourier transform has been applied along the z direction, which is the width of the room. The problem uses a BEM formulation in the frequency domain. The use of analytically appropriate Green's functions for wedges, defined by means of an image model technique, allows the required BEM discretization to be limited to the back and front walls of the room and avoids the discretization of the other flat surfaces. The model allows frequency dependent absorption coefficients to be defined for the various walls. In the case of the ceiling, floor and lateral room surfaces the absorption is introduced through the direct manipulation of the analytical Green's functions. The absorption of the back and front walls is simulated using impedance boundary conditions. © 201 WIT Press.