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arXiv 1602.01626math.NAcs.NA
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快波慢波分裂的光谱延迟修正

Spectral deferred corrections with fast-wave slow-wave splitting

Daniel Ruprecht, Robert Speck

摘要:

本文研究了半隐式谱延迟校正(SISDC)的一种变体,其中刚性,快速动态对应于快速传播的波(“快波慢波问题”)。我们表明,对于标量测试问题的两个虚特征值$i λ_{fast}$,$i λ_{slow}$,有$Δt \left(\left| λ_{fast} \right| + \left| λ_{slow} \right| \right) < 1$是足够的快波慢波SDC(FWSW-SDC)迭代收敛,并在无限快波的限制的收敛速度的非分裂版本被保留。稳定性函数和离散色散关系的推导表明,该方法是稳定的基本上任意快波CFL数,只要慢动力学解决。该方法的数值扩散小,半离散相速度对大波数模式也很精确。性能研究的声学平流问题和线性化Boussinesq方程,描述可压缩,分层流。FWSW-SDC相比,对角隐式龙格-库塔(DIRK)和IMEX龙格-库塔(IMEX)方法,并发现在精度和成本方面具有竞争力。

英文摘要:

The paper investigates a variant of semi-implicit spectral deferred corrections (SISDC) in which the stiff, fast dynamics correspond to fast propagating waves ("fast-wave slow-wave problem"). We show that for a scalar test problem with two imaginary eigenvalues $i λ_{fast}$, $i λ_{slow}$, having $Δt \left(\left| λ_{fast} \right| + \left| λ_{slow} \right| \right) < 1$ is sufficient for the fast-wave slow-wave SDC (FWSW-SDC) iteration to converge and that in the limit of infinitely fast waves the convergence rate of the non-split version is retained. Stability function and discrete dispersion relation are derived and show that the method is stable for essentially arbitrary fast-wave CFL numbers as long as the slow dynamics are resolved. The method causes little numerical diffusion and its semi-discrete phase speed is accurate also for large wave number modes. Performance is studied for an acoustic-advection problem and for the linearised Boussinesq equations, describing compressible, stratified flow. FWSW-SDC is compared to a diagonally implicit Runge-Kutta (DIRK) and IMEX Runge-Kutta (IMEX) method and found to be competitive in terms of both accuracy and cost.

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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