Analysis and comparison of FDTD discretization procedures for room acoustical simulations

Room acoustic simulation techniques have been widely studied in the recent years. Its application ranges over a wide field, e.g., building acoustics, virtual reality or automotive design. Mainly two categories have been formed: geometrical and wave-based methods [1]. The latter include, among others, the finite difference time domain method (FDTD) [2]. In the case of room acoustic simulations in FDTD, the governing equations are usually written as the second-order wave equation [3]. Alternatively, an equivalent system of linear acoustic equations (LAE) of first-order [2] can be employed. Moreover, the full nonlinear Euler equations (NLEE) can be used to consider heat stratifications or flow. Recently, the NLEE were used to compute outdoor sound propagation [4] and modeling of directive sound sources [5]. Moreover, they were incorporated for sound source localization [6]. In this contribution, an analysis of computational aero acoustic (CAA) techniques of spatial and temporal dis- cretization as well as filtering in FDTD regarding room acoustical simulations is presented. Depending on the application, recommendations for the optimal scheme are given. Uncertainties and computational effort of the schemes are discussed