UPML媒质中的包络ADI-FDTD

由于交替方向隐式时域有限差分法(Alternating-Direction Implicit Finite-Difference Time Domain,ADI-FDTD)的数值色散会随着时间步长的增加而增加,文中讨论了单轴各向异性完全匹配层(uniaxial perfectly matched layer,UPML)媒质中包络交替方向隐式时域有限差分法(Envelope ADI-FDTD),推导了二维Envelope ADI-FDTD UPML的迭代公式,并提出一种新的离散方法。与ADI-FDTD UPML相比,改进后的Envelope ADI-FDTD UPML的时间步长可以取得更大,且能有效地修正相速误差,从而减少数值色散,提高计算精度。

Envelope ADI-FDTD in Uniaxial Perfectly Matched Layer Medium

Because the numerical dispersion of the ADI-FDTD method will increase with the increase of the temporal increment,the Envelope ADI-FDTD method in UPML medium is presented in this paper.Two-dimensional formulation for Envelope ADI-FDTD UPML are deduced and a new discrete scheme is presented.Compared with the ADI-FDTD UPML,the temporal increment of the new method can be larger,and the new scheme can improve the phase velocity errors,so the numerical dispersion can be reduced,and the precision of the computation can be improved.