Weak Galerkin methods for second order elliptic interface problems

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Date
2013
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Elsevier
Abstract

Weak Galerkin methods refer to general finite element methods for partial differential equations (PDEs) in which differential operators are approximated by their weak forms as distributions. Such weak forms give rise to desirable flexibilities in enforcing boundary and interface conditions. A weak Galerkin finite element method (WG-FEM) is developed in this paper for solving elliptic PDEs with discontinuous coefficients and interfaces. Theoretically, it is proved that high order numerical schemes can be designed by using the WG-FEM with polynomials of high order on each element. Extensive numerical experiments have been carried out to validate the WG-FEM for solving second order elliptic interface problems. High order of convergence is numerically confirmed in both L-2 and L-infinity norms for the piecewise linear WG-FEM. Special attention is paid to solve many interface problems, in which the solution possesses a certain singularity due to the nonsmoothness of the interface. A challenge in research is to design nearly second order numerical methods that work well for problems with low regularity in the solution. The best known numerical scheme in the literature is of order O(h) to O(h(1.5)) for the solution itself in L-infinity norm. It is demonstrated that the WG-FEM of the lowest order, i.e., the piecewise constant WG-FEM, is capable of delivering numerical approximations that are of order O(h(1.75)) to O(h(2)) in the L-infinity norm for C-1 or Lipschitz continuous interfaces associated with a C-1 or H-2 continuous solution. (C) 2013 Elsevier Inc. All rights reserved.

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Keywords
Finite element methods, Weak Galerkin method, Second order elliptic interface problems, Nonsmooth interface, Low solution regularity, FINITE-ELEMENT-METHOD, BOUNDARY MIB METHOD, MATCHED INTERFACE, DISCONTINUOUS COEFFICIENTS, CONVERGENCE ANALYSIS, FICTITIOUS-DOMAIN, SINGULAR SOURCES, BLOOD-FLOW, EQUATIONS, DISCRETIZATION, Computer Science, Interdisciplinary Applications, Physics, Mathematical
Citation
Mu, L., Wang, J., Wei, G., Ye, X., & Zhao, S. (2013). Weak Galerkin methods for second order elliptic interface problems. In Journal of Computational Physics (Vol. 250, pp. 106–125). Elsevier BV. https://doi.org/10.1016/j.jcp.2013.04.042