A technique based on the combination of Fourier pseudospectral method and the perfectly matched layer (PML) is developed to simulate transient acoustic wave propagation in multidimensional, inhomogeneous, absorptive m...
详细信息
A technique based on the combination of Fourier pseudospectral method and the perfectly matched layer (PML) is developed to simulate transient acoustic wave propagation in multidimensional, inhomogeneous, absorptive media. Instead of the finite difference approximation in the conventional finite-difference time-domain (FDTD) method, this technique uses trigonometric functions, through an FFT (fast Fourier transform) algorithm, to represent the spatial derivatives in partial differential equations. Traditionally the Fourier pseudospectral method is used only for spatially periodic problems because the use of FFT implies periodicity. In order to overcome this limitation, the perfectly matched layer is used to attenuate the waves from other periods, thus allowing the method to be applicable to unbounded media. This new algorithm, referred to as the pseudospectraltime-domain (PSTD) algorithm, is developed to solve large-scale problems for acoustic waves. It has an infinite order of accuracy in the spatial derivatives, and thus requires much fewer unknowns than the conventional FDTD method. Numerical results confirms the efficacy of the PSTD method.
This paper makes a comparison study by using both the pseudospectraltime-domain (PSTD) and finite-difference time-domain (FDTD) methods for a two-dimensional (2-D) scattering analysis. The time-domain incident plane-...
详细信息
This paper makes a comparison study by using both the pseudospectraltime-domain (PSTD) and finite-difference time-domain (FDTD) methods for a two-dimensional (2-D) scattering analysis. The time-domain incident plane-wave pulse used in the PSTD technique is herewith simulated with an initial-condition excitation technique to eliminate the unwanted Gibbs phenomenon. The pure scattered-field formulation is utilized to surmount the difficulty of generation of the incident field, and a PSTD near-to-far-zone field transform is developed for the analysis of the scattering width (SW) of targets. It is found that the PSTD computed results agree well with those derived from the FDTD method, while the PSTD requires much less computational space and CPU time. (C) 2000 John Wiley & Sons, Inc.
暂无评论