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arXiv 1806.02018math.NAcs.NA
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具有变量系数的间断伽辽金方法的误差有界性

Error Boundedness of Discontinuous Galerkin Methods with Variable Coefficients

Philipp Öffner, Hendrik Ranocha

AI总结:

本文研究了在超几何守恒律和通量重建方案中,具有变量系数的间断伽辽金谱元框架下,长时间误差的行为,分析了不同数值通量和基函数对误差增长和渐进行为的影响,并推导了保证误差随时间有界的条件。

摘要:

对于实际应用,时间依赖偏微分方程数值解的长时间行为非常重要。本文在超几何守恒律和通量重建方案的背景下,研究了具有变量系数的间断伽辽金谱元框架下的方案。对于具有常系数的线性问题,文献中已知数值通量(如中心或迎风)和基函数(如高斯-legendre或高斯-legendre-legendre)的选择会影响误差的增长率和渐进行为。本文扩展了这些对长时间误差的研究,使用高斯-legendre和高斯-legendre-legendre节点以及几种数值通量。我们推导出保证误差随时间有界的条件。此外,我们在这些条件下分析误差行为,并在多个数值测试中展示了与常系数情况的相似性。然而,如果这些条件被违反,误差会表现出完全不同的行为。确实,通过应用中心数值通量,误差会无限制地增加,而迎风数值通量仍然可以导致均匀有界的数值误差。对此现象的解释证实了我们的分析研究。

英文摘要:

For practical applications, the long time behaviour of the error of numerical solutions to time-dependent partial differential equations is very important. Here, we investigate this topic in the context of hyperbolic conservation laws and flux reconstruction schemes, focusing on the schemes in the discontinuous Galerkin spectral element framework. For linear problems with constant coefficients, it is well-known in the literature that the choice of the numerical flux (e.g. central or upwind) and the selection of the polynomial basis (e.g. Gauß-Legendre or Gauß-Lobatto-Legendre) affects both the growth rate and the asymptotic value of the error. Here, we extend these investigations of the long time error to variable coefficients using both Gauß-Lobatto-Legendre and Gauß-Legendre nodes as well as several numerical fluxes. We derive conditions guaranteeing that the errors are still bounded in time. Furthermore, we analyse the error behaviour under these conditions and demonstrate in several numerical tests similarities to the case of constant coefficients. However, if these conditions are violated, the error shows a completely different behaviour. Indeed, by applying central numerical fluxes, the error increases without upper bound while upwind numerical fluxes can still result in uniformly bounded numerical errors. An explanation for this phenomenon is given, confirming our analytical investigations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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