空间高阶差分近似对三维ADI-FDTD数值色散的影响

Numerical dispersion analysis for 3-D ADI-FDTD method using higher-order spatial difference

研究采用空间高阶差分近似的三维交替方向隐式时域有限差分法(ADIFDTD,AlternatingDirectionImplicitFiniteDifferenceTimeDomain)数值色散问题,首先推导了采用空间高阶差分近似的数值色散迭代公式,分别对最小相速方向和最大相速方向进行二阶、四阶、六阶、十阶空间差分数值色散误差的数值计算和比较,并分析数值色散对空间差分阶数的依赖关系,最后发现在均匀网格中采用四阶空间差分能得到较好的效果.

Attention was focused on the numerical dispersion property of 3-D ADI-FDTD (alternating-direction implicit finite-difference time-domain) method using the higher-order spatial difference. First, the iterative formulas of the numerical dispersion relation for the higher-order spatial difference were derived. And secondly, the numerical dispersion values were computed and compared for the second-order, fourth-order, sixth-order and tenth-order spatial difference along the maximum phase-velocity direction and the minimum phase-velocity direction, respectively. And consequently the numerical dispersion was investigated as a function of higher-order spatial difference. Finally it is found that the fourth-order spatial difference is better than others for the uniform cell case.