Method for implementing PML (perfectly matched layers) in DGTD (discontinuous Galerkin time domain) by aid of hybrid triangular prism-tetrahedron grids

Abstract

The invention discloses a method for implementing PML (perfectly matched layers) in DGTD (discontinuous Galerkin time domains) by the aid of hybrid triangular prism-tetrahedron grids. The method includes steps of S1, selecting computational models, selecting PML absorption layers and establishing Maxwell equations for PML zones and non-PML zones in computational domains; S2, dividing grids and guaranteeing that the grids on primary surfaces and secondary surfaces of periodic boundaries are matched with one another; S3, expanding electric field intensity vectors and magnetic field intensity vectors in the grids in different regions by the aid of different basis functions; S4, carrying out space discretization by the aid of DGTD algorithms and then carrying out time discretization to obtaintime discretization equations; S5, integrating element matrixes and acquiring solved element matrixes according to conditions; S6, carrying out time iteration to obtain electric field and magnetic field values at each moment. The method has the advantages that the grids in PML regions are divided into triangular prisms, accordingly, the computational precision can be controlled from two dimensions, and the method is excellent in adaptability to hierarchical characteristics of the PML and is good in solving precision and high in solving speed.

Description

technical field [0001] The invention belongs to the technical field of three-dimensional electromagnetic field numerical solution, in particular to a method for realizing PML in DGTD by using a mixed triangular prism-tetrahedron grid. Background technique [0002] With the development of computational electromagnetism, methods such as finite element and finite difference have been widely used to deal with related problems. However, due to the limitations of finite difference and finite element method itself, the time-domain discontinuous Galerkin method (DGTD) was proposed abroad. Deals with some problems in computational electromagnetism. Compared with finite elements and finite differences, DGTD can be applied to more complex scenarios such as complex electromagnetic environments, large-scale multi-scale problems, etc., and DGTD can well support parallel computing. Based on this, DGTD is used to deal with computational electromagnetics. The problem will greatly speed up t...

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Problems solved by technology

However, the design of the perfect matching layer is complex and the calculation is cumbersome. At the same time, the mesh division of the PML area and the selection of the area size have a great impact on the accuracy and calculation amount.

[0004] In order to make the PML area have a better absorption effect, the current method is generally to encrypt the grid, but with the grid encryption, the calculation amount will increase sharply. For the current tetrahedral grid, although it can be applied to any different The structure of regular shape, but because of its own too many unknowns will make the calculation amount larger than the case of regular grid division, it cannot efficiently and accurately solve the PML truncation problem in computational electromagnetics

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