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Order Two Superconvergence of the CDG Finite Elements on Triangular and Tetrahedral Meshes

Order Two Superconvergence of the CDG Finite Elements on Triangular and Tetrahedral Meshes

Year:    2023

Author:    Xiu Ye, Shangyou Zhang

CSIAM Transactions on Applied Mathematics, Vol. 4 (2023), Iss. 2 : pp. 256–274

Abstract

It is known that discontinuous finite element methods use more unknown variables but have the same convergence rate comparing to their continuous counterpart. In this paper, a novel conforming discontinuous Galerkin (CDG) finite element method is introduced for Poisson equation using discontinuous $P_k$ elements on triangular and tetrahedral meshes. Our new CDG method maximizes the potential of discontinuous $P_k$ element in order to improve the convergence rate. Superconvergence of order two for the CDG finite element solution is proved in an energy norm and in the $L^2$ norm. A local post-process is defined which lifts a $P_k$ CDG solution to a discontinuous $P_{k+2}$ solution. It is proved that the lifted $P_{k+2}$ solution converges at the optimal order. The numerical tests confirm the theoretic findings. Numerical comparison is provided in 2D and 3D, showing the $P_k$ CDG finite element is as good as the $P_{k+2}$ continuous Galerkin finite element.

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Journal Article Details

Publisher Name:    Global Science Press

Language:    English

DOI:    https://doi.org/10.4208/csiam-am.SO-2021-0051

CSIAM Transactions on Applied Mathematics, Vol. 4 (2023), Iss. 2 : pp. 256–274

Published online:    2023-01

AMS Subject Headings:    Global Science Press

Copyright:    COPYRIGHT: © Global Science Press

Pages:    19

Keywords:    Finite element conforming discontinuous Galerkin method stabilizer free triangular grid tetrahedral grid.

Author Details

Xiu Ye

Shangyou Zhang

  1. Constructing a CDG Finite Element with Order Two Superconvergence on Rectangular Meshes

    Ye, Xiu | Zhang, Shangyou

    Communications on Applied Mathematics and Computation, Vol. (2023), Iss.

    https://doi.org/10.1007/s42967-023-00330-5 [Citations: 0]
  2. Two-Order Superconvergent CDG Finite Element Method for the Heat Equation on Triangular and Tetrahedral Meshes

    Ye, Xiu | Zhang, Shangyou

    Communications on Applied Mathematics and Computation, Vol. (2024), Iss.

    https://doi.org/10.1007/s42967-024-00444-4 [Citations: 0]
  3. Order two superconvergence of the CDG finite elements for non-self adjoint and indefinite elliptic equations

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    Advances in Computational Mathematics, Vol. 50 (2024), Iss. 1

    https://doi.org/10.1007/s10444-023-10100-9 [Citations: 1]
  4. Four-order superconvergent CDG finite elements for the biharmonic equation on triangular meshes

    Ye, Xiu | Zhang, Shangyou

    Journal of Computational and Applied Mathematics, Vol. 440 (2024), Iss. P.115516

    https://doi.org/10.1016/j.cam.2023.115516 [Citations: 1]
  5. A superconvergent CDG finite element for the Poisson equation on polytopal meshes

    Ye, Xiu | Zhang, Shangyou

    ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, Vol. 104 (2024), Iss. 3

    https://doi.org/10.1002/zamm.202300521 [Citations: 0]
  6. Superconvergent P1 honeycomb virtual elements and lifted P3 solutions

    Lin, Yanping | Xu, Xuejun | Zhang, Shangyou

    Calcolo, Vol. 61 (2024), Iss. 4

    https://doi.org/10.1007/s10092-024-00618-9 [Citations: 0]
  7. A pressure-robust stabilizer-free WG finite element method for the Stokes equations on simplicial grids

    Yang, Yan | Ye, Xiu | Zhang, Shangyou

    Electronic Research Archive, Vol. 32 (2024), Iss. 5 P.3413

    https://doi.org/10.3934/era.2024158 [Citations: 0]