Communications on Applied Mathematics and Computation ›› 2022, Vol. 4 ›› Issue (3): 759-782.doi: 10.1007/s42967-021-00144-3

• ORIGINAL PAPER •    下一篇

How to Design a Generic Accuracy-Enhancing Filter for Discontinuous Galerkin Methods

Xiaozhou Li   

  1. School of Mathematical Sciences, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China
  • 收稿日期:2020-08-30 修回日期:2021-04-26 出版日期:2022-09-20 发布日期:2022-07-04
  • 通讯作者: Xiaozhou Li,E-mail:xiaozhouli@uestc.edu.cn E-mail:xiaozhouli@uestc.edu.cn
  • 基金资助:
    The authors would like to thank the reviewers for their helpful comments and suggestions in the revision of this manuscript.

How to Design a Generic Accuracy-Enhancing Filter for Discontinuous Galerkin Methods

Xiaozhou Li   

  1. School of Mathematical Sciences, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China
  • Received:2020-08-30 Revised:2021-04-26 Online:2022-09-20 Published:2022-07-04
  • Contact: Xiaozhou Li,E-mail:xiaozhouli@uestc.edu.cn E-mail:xiaozhouli@uestc.edu.cn
  • Supported by:
    The authors would like to thank the reviewers for their helpful comments and suggestions in the revision of this manuscript.

摘要: Higher order accuracy is one of the well-known beneficial properties of the discontinuous Galerkin (DG) method. Furthermore, many studies have demonstrated the superconvergence property of the semi-discrete DG method. One can take advantage of this superconvergence property by post-processing techniques to enhance the accuracy of the DG solution. The smoothness-increasing accuracy-conserving (SIAC) filter is a popular post-processing technique introduced by Cockburn et al. (Math. Comput. 72(242): 577–606, 2003). It can raise the convergence rate of the DG solution (with a polynomial of degree k) from order $ k+1 $ to order $2k+1$ in the $ L^2 $ norm. This paper first investigates general basis functions used to construct the SIAC filter for superconvergence extraction. The generic basis function framework relaxes the SIAC filter structure and provides flexibility for more intricate features, such as extra smoothness. Second, we study the distribution of the basis functions and propose a new SIAC filter called compact SIAC filter that significantly reduces the support size of the original SIAC filter while preserving (or even improving) its ability to enhance the accuracy of the DG solution. We prove the superconvergence error estimate of the new SIAC filters. Numerical results are presented to confirm the theoretical results and demonstrate the performance of the new SIAC filters.

关键词: Discontinuous Galerkin method, Superconvergence, Smoothness-increasing accuracy-conserving (SIAC) filter, Convolution filtering, Post-processing

Abstract: Higher order accuracy is one of the well-known beneficial properties of the discontinuous Galerkin (DG) method. Furthermore, many studies have demonstrated the superconvergence property of the semi-discrete DG method. One can take advantage of this superconvergence property by post-processing techniques to enhance the accuracy of the DG solution. The smoothness-increasing accuracy-conserving (SIAC) filter is a popular post-processing technique introduced by Cockburn et al. (Math. Comput. 72(242): 577–606, 2003). It can raise the convergence rate of the DG solution (with a polynomial of degree k) from order $ k+1 $ to order $2k+1$ in the $ L^2 $ norm. This paper first investigates general basis functions used to construct the SIAC filter for superconvergence extraction. The generic basis function framework relaxes the SIAC filter structure and provides flexibility for more intricate features, such as extra smoothness. Second, we study the distribution of the basis functions and propose a new SIAC filter called compact SIAC filter that significantly reduces the support size of the original SIAC filter while preserving (or even improving) its ability to enhance the accuracy of the DG solution. We prove the superconvergence error estimate of the new SIAC filters. Numerical results are presented to confirm the theoretical results and demonstrate the performance of the new SIAC filters.

Key words: Discontinuous Galerkin method, Superconvergence, Smoothness-increasing accuracy-conserving (SIAC) filter, Convolution filtering, Post-processing

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