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arXiv 2103.16158math.NAcs.NA
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双曲型偏微分方程连续FEM的谱分析:逼近、稳定化和时间步进的影响

Spectral analysis of continuous FEM for hyperbolic PDEs: influence of approximation, stabilization, and time-stepping

Sixtine Michel, Davide Torlo, Mario Ricchiuto, Rémi Abgrall

摘要:

研究一维双曲型偏微分方程的连续有限元离散。本文的主要贡献是提供了一个完全离散的谱分析,这是用来建议最优值的CFL数和涉及不同类型的稳定运营商的稳定参数。特别地,我们分析了流线迎风Petrov-Galerkin(SUPG)稳定技术,连续内部惩罚(CIP)稳定方法和局部投影稳定(LPS)。比较了连续有限元空间的三种不同选择:伯恩斯坦多项式、等间距节点上的拉格朗日多项式和Gauss-Lobatto立方节点上的拉格朗日多项式。对于最后一种选择,我们只考虑基于与单元的自由度对应的公式的不精确求积,这允许获得完全对角质量矩阵。我们还比较了不同的时间推进策略,即龙格库塔(RK),强稳定性保持RK(SSPRK)和延迟校正时间积分方法。后者允许减轻计算成本,因为质量矩阵求逆由高阶校正迭代代替。为了理解这些选择的效果,执行时间连续和完全离散的傅里叶分析。这些允许在准确性和稳定性方面比较所有不同的组合,以及为所涉及的最优值离散化参数提供建议。在线性和非线性问题上的数值结果得到了彻底的验证,并提供了错误-CPU时间曲线。我们的最终结论表明,容积元件结合SSPRK和CIP或LPS稳定是最有前途的组合。

英文摘要:

We study continuous finite element dicretizations for one dimensional hyperbolic partial differential equations. The main contribution of the paper is to provide a fully discrete spectral analysis, which is used to suggest optimal values of the CFL number and of the stabilization parameters involved in different types of stabilization operators. In particular, we analyze the streamline-upwind Petrov-Galerkin (SUPG) stabilization technique, the continuous interior penalty (CIP) stabilization method and the local projection stabilization (LPS). Three different choices for the continuous finite element space are compared: Bernstein polynomials, Lagrangian polynomials on equispaced nodes, and Lagrangian polynomials on Gauss-Lobatto cubature nodes. For the last choice, we only consider inexact quadrature based on the formulas corresponding to the degrees of freedom of the element, which allows to obtain a fully diagonal mass matrix. We also compare different time stepping strategies, namely Runge-Kutta (RK), strong stability preserving RK (SSPRK) and deferred correction time integration methods. The latter allows to alleviate the computational cost as the mass matrix inversion is replaced by the high order correction iterations. To understand the effects of these choices, both time-continuous and fully discrete Fourier analysis are performed. These allow to compare all the different combinations in terms of accuracy and stability, as well as to provide suggestions for optimal values discretization parameters involved. The results are thoroughly verified numerically both on linear and non-linear problems, and error-CPU time curves are provided. Our final conclusions suggest that cubature elements combined with SSPRK and CIP or LPS stabilization are the most promising combinations.

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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