arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2302.01092math.NAcs.NA
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自适应指数多算子分裂方法的构造

Construction of adaptive exponential multi-operator splitting methods

Othmar Koch, Koray Acar, Winfried Auzinger, Daniel Hoffmann, Friedrich Kupka, Benedikt Moser

AI总结:

本文针对磁流体力学方程构造了基于正系数三算子或四算子分裂的自适应指数方法,通过优化主导局部误差项得到新系数与误差估计器,并在粘性 Burgers 方程的激波状行为中验证了方法的有效性。

摘要:

我们构造了适用于求解磁流体力学(MHD)方程的分裂方法。由于所涉及算子的物理意义,将方程分裂为三个甚至四个具有正系数的算子,对于物理上正确且高效地求解方程是合适的。为了高效地获得精确的近似解,时间步长的自适应选择非常重要,尤其是考虑到系统具有非光滑动力学特性。因此,我们通过优化主导局部误差项,构造了新的方法系数以及相应的误差估计器。作为概念验证,我们证明了自适应分裂能够在粘性 Burgers 方程出现激波状行为时,依然忠实地反映解的行为;该方程作为一个简化的模型问题,展现了不可压缩流动的 Navier-Stokes 方程的若干特征。

英文摘要:

We construct splitting methods suitable for the solution of the equations of magnetohydrodynamics (MHD). Due to the physical significance of the involved operators, splittings into three or even four operators with positive coefficients are appropriate for a physically correct and efficient solution of the equations. To efficiently obtain an accurate solution approximation, adaptive choice of the time-steps is important particularly in the light of the unsmooth dynamics of the system. Thus, we construct new method coefficients in conjunction with associated error estimators by optimizing the leading local error term. As a proof of concept, we demonstrate that adaptive splitting faithfully reflects the solution behavior also in the presence of a shock-like behavior for the viscous Burgers equation, which serves as a simplified model problem displaying several features of the Navier-Stokes equation for incompressible flow.

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