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Analysis of optimal superconvergence of an ultraweak-local discontinuous Galerkin method for a time dependent fourth-order equation
- Source :
- ESAIM: Mathematical Modelling and Numerical Analysis; November 2020, Vol. 54 Issue: 6 p1797-1820, 24p
- Publication Year :
- 2020
-
Abstract
- In this paper, we study superconvergence properties of the ultraweak-local discontinuous Galerkin (UWLDG) method in Tao et al.[To appear in Math. Comput.DOI: https://doi.org/10.1090/mcom/3562(2020).] for an one-dimensional linear fourth-order equation. With special initial discretizations, we prove the numerical solution of the semi-discrete UWLDG scheme superconverges to a special projection of the exact solution. The order of this superconvergence is proved to be k+ min(3, k) when piecewise ℙkpolynomials with k≥ 2 are used. We also prove a 2k-th order superconvergence rate for the cell averages and for the function values and derivatives of the UWLDG approximation at cell boundaries. Moreover, we prove superconvergence of (k+ 2)-th and (k+ 1)-th order of the function values and the first order derivatives of the UWLDG solution at a class of special quadrature points, respectively. Our proof is valid for arbitrary non-uniform regular meshes and for arbitrary k≥ 2. Numerical experiments verify that all theoretical findings are sharp.
Details
- Language :
- English
- ISSN :
- 0764583X and 12903841
- Volume :
- 54
- Issue :
- 6
- Database :
- Supplemental Index
- Journal :
- ESAIM: Mathematical Modelling and Numerical Analysis
- Publication Type :
- Periodical
- Accession number :
- ejs53934291
- Full Text :
- https://doi.org/10.1051/m2an/2020023