用时域有限差分法计算透声目标的散射场

Computation of sound scattering from penetrable objects using finite difference time domain method

在透声界面附近运用声学基本方程可导出边界条件的时域有限差分（ＦＤＴＤ）表达式。本文用ＦＤＴＤ计算透声物体的反射、透射和散射，并讨论全内反射和完全透射现象，所得到的结果与理论解相符合，从而验证了这一边界条件差分表达式的适用性。基于此边界条件的ＦＤＴＤ基本框架可望在解决各种非弹性体的散射问题中有广泛的应用。

Abstract From the basic equations in acoustics, boundary condition expressions on penetrable interfaces between media can be derived for the finite difference time domain (FDTD) method. In this work, FDTD is applied to compute sound reflection, transmission and scattering. The phenomena of total internal reflection and total transmission are discussed. The FDTD boundary expressions are verified by numerical results which conform to the well known theoretical solutions. The FDTD framework based on these boundary expressions is useful in solving problems involving scattering from various non elastic objects. An effective absorbing boundary condition is also proposed.