AN L^(∞) SECOND ORDER CARTESIAN METHOD FOR 3D ANISOTROPIC INTERFACE PROBLEMS  

作　　者：Baiying Dong Xiufeng Feng Zhilin Li 

机构地区：[1]School of Mathematics and Statistics,NingXia University,Yinchuan 750021,China [2]School of Mathematics and Computer Science,NingXia Normal University,Guyuan 756000,China [3]Department of Mathematics,North Carolina State University,Raleigh,NC 27695-8205,USA

出　　处：《Journal of Computational Mathematics》2022年第6期882-912,共31页计算数学（英文）

基　　金：Zhilin Li is partially supported by Simon’s grant 633724.Xiufang Feng is partially supported by CNSF Grant No.11961054;Baiying Dong is partially supported by Ningxia Natural Science Foundation of China Grant No.2021AAC03234.

摘　　要：A second order accurate method in the infinity norm is proposed for general three dimensional anisotropic elliptic interface problems in which the solution and its derivatives,the coefficients,and source terms all can have finite jumps across one or several arbitrary smooth interfaces.The method is based on the 2D finite element-finite difference(FEFD)method but with substantial differences in method derivation,implementation,and convergence analysis.One of challenges is to derive 3D interface relations since there is no invariance anymore under coordinate system transforms for the partial differential equations and the jump conditions.A finite element discretization whose coefficient matrix is a symmetric semi-positive definite is used away from the interface;and the maximum preserving finite difference discretization whose coefficient matrix part is an M-matrix is constructed at irregular elements where the interface cuts through.We aim to get a sharp interface method that can have second order accuracy in the point-wise norm.We show the convergence analysis by splitting errors into several parts.Nontrivial numerical examples are presented to confirm the convergence analysis.

关 键 词：3D anisotropic PDE Cartesian meshes Finite element method Finite difference method Maximum preserving IIM Convergence analysis 

分 类 号：O17[理学—数学]