Optimal convergence of local discontinuous Galerkin methods for convection-diffusion equations

Fuente: arXiv
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Main Authors: Liu, Wenjie, Xie, Ruiyi, Wang, Li-Lian, Zhang, Zhimin
Format: Preprint
Published: 2026
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_version_ 1866910040382767104
author Liu, Wenjie
Xie, Ruiyi
Wang, Li-Lian
Zhang, Zhimin
author_facet Liu, Wenjie
Xie, Ruiyi
Wang, Li-Lian
Zhang, Zhimin
contents The $hp$ local discontinuous Galerkin (LDG) method proposed by Castillo et al. [Math. Comp.,~71 (238): 455-478, 2002] has been shown to be an efficient approach for solving convection-diffusion equations. However, theoretical analysis indicates that, for solutions with limited spatial regularity, the method exhibits suboptimal convergence in $p$, suffering a loss of one order, comparing to numerical experiments. The purpose of this paper is to close the gap between theoretical estimates and numerical evidence. This is accomplished by establishing new approximation results for the associated Gauss-Radau projections of functions in suitable function spaces that can optimally characterize the regularity of singular solutions. We show that such a framework arises aturally and enables the study of various types of singular solutions, with full consistency between theoretical analysis and numerical results. This investigation sheds light on the resolution of the suboptimality in $p$ observed in the literature for several other types of DG schemes in different settings.
format Preprint
id arxiv_https___arxiv_org_abs_2603_03847
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Optimal convergence of local discontinuous Galerkin methods for convection-diffusion equations
Liu, Wenjie
Xie, Ruiyi
Wang, Li-Lian
Zhang, Zhimin
Numerical Analysis
41A10, 41A25, 65M60, 65N30
The $hp$ local discontinuous Galerkin (LDG) method proposed by Castillo et al. [Math. Comp.,~71 (238): 455-478, 2002] has been shown to be an efficient approach for solving convection-diffusion equations. However, theoretical analysis indicates that, for solutions with limited spatial regularity, the method exhibits suboptimal convergence in $p$, suffering a loss of one order, comparing to numerical experiments. The purpose of this paper is to close the gap between theoretical estimates and numerical evidence. This is accomplished by establishing new approximation results for the associated Gauss-Radau projections of functions in suitable function spaces that can optimally characterize the regularity of singular solutions. We show that such a framework arises aturally and enables the study of various types of singular solutions, with full consistency between theoretical analysis and numerical results. This investigation sheds light on the resolution of the suboptimality in $p$ observed in the literature for several other types of DG schemes in different settings.
title Optimal convergence of local discontinuous Galerkin methods for convection-diffusion equations
topic Numerical Analysis
41A10, 41A25, 65M60, 65N30
url https://arxiv.org/abs/2603.03847