Numerical simulation method of sound propagation in enclosed spaces with non-flat walls.

Accurate calculation of acoustic pressure field in enclosed spaces by room acoustic software is one of the main research concerns in room acoustics. Therefore, many numerical simulation methods have been developed, but even the most recent ones force us to make compromises in terms of accuracy, size of simulated domains, or bandwidth of calculation. This study is about the development of a numerical simulation method of sound propagation in enclosed spaces with an accurate consideration of the influence induced by geometrical irregularities on the room’s walls (acoustic diffusion). This method is based on the Adaptive Rectangular Decomposition method (ARD) with boundary conditions based on the Finite-Difference Time-Domain method (FDTD). This method was chosen because it allows the computation of rather large rooms faster than a Finite Element Method while minimizing frequency dispersion and errors induced by an FDTD-based method. In order to validate the developed model and especially the simulation of sound propagation in an enclosed space, it was compared with an image source model. Then, it was compared with a Kobayashi Potential-based method to validate the simulation of the reflection on non-flat walls. Finally, the numerical model was compared with experimental measurements performed in a real room.