“总场-散射场源”在波动方程时域有限差分法中的应用研究

Application of "TF-SF Source" in the Wave-equation Finite-difference Time-domain Method

研究了"总场-散射场源"在波动方程时域有限差分法(WEFDTD)中的应用方法,这一问题的难点是如何把基本差分格式应用于总场区和散射场区的分界面。具体做法是将激励源设置在两区域的分界面上,并基于总场-散射场原理对基本差分格式加以修正,使得用其刷新某一网格点的总场值或散射场值时,该点周围四个网格点能同时提供总场值或散射场值。这一技术有效地克服了WEFDTD的已有激励源的不足。使用这一技术,数值模拟了简谐波和高斯脉冲的传播过程,发现计算结果和解析解符合得很好。

The technique of implement of the ＂TF-SF source＂ in the wave-equation finite-difference time-domain method（WEFDTD） is researched,and the difficulty of the problem is how to use the basic difference equation in the boundary of the total field region and scattering field region.The implement method in WEFDTD is as follow： set the exciting source on the boundaries of the 2 regions,and make some modifications to the difference equations on the 2 region boundaries based on the total field-scattering field principle,so as to calculate the total field or scattering field of a certain cell,the 4 cells around the cell can all provide total field or scattering field.The exciting source can eliminate the defects of the other sources of the WEFDTD.Using the technology,numerical experiments that simulate the radiations of a harmonic wave and a Gauss impulse was done,and the calculated results was found coincident to the analytic results very well.