Finite Volume Time Domain simulations of frequency-dependent boundary conditions and absorbing layer

Accurate calculation of both early reflections and the reverberant field of an enclosed space requires accurate boundary modeling in terms of both spatial geometry and absorbing conditions. Within the framework of time-domain room acoustics simulations, the finite volume (FV) method allows to derive a scheme over unstructured grids, which is a feature of interest for the approximation of irregular boundaries. The frequency-dependence of FV boundaries has not been explored in detail yet beyond energy conservation. The present communication investigates both frequency-independent and frequency-dependent boundary conditions for the FV method comparing reflection coefficient magnitudes. The numerical results obtained for reflection coefficients are in agreement with the theory for a large span of angles and frequencies. In addition, an absorbing layer is proposed and compared to a matched absorbing boundary condition.