Underwater broadband acoustic scattering modelling based on FDTD

Abstract

A modified finite-difference time-domain (FDTD) method is described in this paper. The absorption coefficient which is frequency-dependent is considered, and it is used to compute broadband acoustic scattering model of underwater complex object. The perfectly matched layer (PML) absorbing boundary condition (ABC) is applied to this work. Considering computation and accuracy comprehensively, PML boundary layer number and the attenuation coefficient is set at proper values. Computer Graphics are applied to mesh-generating of the irregular object. A pulse of LFM signal is used to simulate wide-band acoustic scattering field of a circle in 2D and a complex object in 3D. And the scattered acoustic pressure waveforms of some certain points are computed in the calculation field. Results obtained from simulation confirm the high accuracy of the proposed method.