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arXiv 0706.2895math.NAcs.NAmath.AP
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降维作为网格细化和跟踪PDE奇点的工具

Dimensional reduction as a tool for mesh refinement and tracking singularities of PDEs

Department of Mathematics(数学系);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室)

Panagiotis Stinis

AI总结:

提出利用降维技术进行网格细化并研究时间相关偏微分方程可能奇点的一系列算法,灵感来自统计力学中评估临界点附近系统性质的方法。

摘要:

我们提出了一系列利用降维进行网格细化并研究时间相关偏微分方程可能奇点解的算法。这些算法受统计力学中用于评估临界点附近系统性质的构造启发。第一个算法允许精确确定可能奇点发生的时间。第二个算法是一种自适应网格细化方案,可用于高效逼近可能的奇点。最后,第三个算法使用第二个算法直到可用分辨率耗尽(当我们接近可能的奇点时),然后切换到降维模型,该模型在准确时能够忠实跟踪所声称奇点发生时间之后的解。准确的降维模型应以正确的速率耗散能量。我们为每个算法构建了两个变体。第一个变体假设我们实际知道降维模型。第二个变体假设我们知道降维模型的形式,即模型中出现的项,但不一定知道其系数。在这种情况下,我们还提供了一种确定系数的方法。我们给出了零粘度和非零粘度Burgers方程的数值结果,以说明这些算法的使用。

英文摘要:

We present a collection of algorithms which utilize dimensional reduction to perform mesh refinement and study possibly singular solutions of time-dependent partial differential equations. The algorithms are inspired by constructions used in statistical mechanics to evaluate the properties of a system near a critical point. The first algorithm allows the accurate determination of the time of occurrence of a possible singularity. The second algorithm is an adaptive mesh refinement scheme which can be used to approach efficiently the possible singularity. Finally, the third algorithm uses the second algorithm until the available resolution is exhausted (as we approach the possible singularity) and then switches to a dimensionally reduced model which, when accurate, can follow faithfully the solution beyond the time of occurrence of the purported singularity. An accurate dimensionally reduced model should dissipate energy at the right rate. We construct two variants of each algorithm. The first variant assumes that we have actual knowledge of the reduced model. The second variant assumes that we know the form of the reduced model, i.e. the terms appearing in the reduced model, but not necessarily their coefficients. In this case, we also provide a way of determining the coefficients. We present numerical results for the Burgers equation with zero and nonzero viscosity to illustrate the use of the algorithms.

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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