两种适用于时域有限体积方法的截断边界

Two boundary conditions for the truncation of cell-centered FVTD algorithm on unstructured lattices

将广泛用于时域有限差分（FDTD）的各向异性完全匹配层推广到非结构网格下格子中心型时域有限体积方法（UCFVTD）中，并同Silver-Mtiller截断边界相结合，提出了一种适用于UCFVTD的截断边界条件。将良态完全匹配层推广到三维UCFVTD计算，给出了三维情况下UCFVTD算法在良态完全匹配层中的场方程。通过数值反射试验以及对典型的电磁场散射问题的计算，验证了这两种截断边界条件的有效性和整体算法的稳定性。同以往的Silver—Muller吸收边界比较，反射误差分别有15～25dB和17～28dB改善，提高了计算精度。

The anisotropic perfectly matched layer（A-PML） being used in FDTD algorithm broadly is adapted for the cell-centered finite-volume time-domain（FVTD） algorithm on unstructured meshes（UCFVTD） . Combined with the Silver-Mtiller absorbing boundary condition （ABC）, a boundary condition is presented for the truncation of UCFVTD lattices. The well-Posed PML is adapted for 3D UCFVTD algorithm and the 3D field equations in the well-Posed PML are shown clearly. The numerical reflecting trials and the example of scattering calculation demonstrate that the two methods are valid and the UCFVTD implementations of them are stable. The presented two methods can suppress the reflecting against 15-25 dB and 17-28 dB more than the traditional Silver-Muller ABC respectively, and therefore have higher computational precision.