论文标题

一种通用的线性方法方法,用于设计和优化CFD中有效,准确且易于实现的时间步变方法

A general linear method approach to the design and optimization of efficient, accurate, and easily implemented time-stepping methods in CFD

论文作者

DeCaria, Victor, Gottlieb, Sigal, Grant, Zachary J., Layton, William J.

论文摘要

在模拟流体运动时间的模拟中,精度已被证明是难以捉摸的。我们寻求具有足够稳定性的高度准确的方法来处理许多流的量表。这些方法还必须易于在当前复杂的(可能是遗产代码)中实现。在此,我们开发,分析和测试了解决这两个问题的新时间步进方法,目的是加快满足应用需求的时间准确方法的开发。新方法是通过向已在现有代码中实现和测试的流行方法引入廉价的预过滤和过滤后的步骤来创建的。我们表明,对多步或多阶段方法进行过滤和过滤后进行过滤会导致具有多个步骤和阶段的新方法:这些是通用线性方法(GLMS)。我们利用GLM的精心研究的属性来了解过滤方法的准确性和稳定性,并为流行的时间步变方法设计最佳的新滤镜。我们介绍了具有低精度方法具有低认知复杂性和出色稳定性的高精度方法的新嵌入式家庭。提出了这些方法的数值测试,包括找到某些方法的故障点。在提出的新方法中,有一对新型的交替过滤器,用于隐式Euler方法,该方法诱导了三阶,稳定的误差抑制方案,该方案被证明特别有效。

In simulations of fluid motion time accuracy has proven to be elusive. We seek highly accurate methods with strong enough stability properties to deal with the richness of scales of many flows. These methods must also be easy to implement within current complex, possibly legacy codes. Herein we develop, analyze and test new time stepping methods addressing these two issues with the goal of accelerating the development of time accurate methods addressing the needs of applications. The new methods are created by introducing inexpensive pre-filtering and post-filtering steps to popular methods which have been implemented and tested within existing codes. We show that pre-filtering and post-filtering a multistep or multi-stage method results in new methods which have both multiple steps and stages: these are general linear methods (GLMs). We utilize the well studied properties of GLMs to understand the accuracy and stability of filtered method, and to design optimal new filters for popular time-stepping methods. We present several new embedded families of high accuracy methods with low cognitive complexity and excellent stability properties. Numerical tests of the methods are presented, including ones finding failure points of some methods. Among the new methods presented is a novel pair of alternating filters for the Implicit Euler method which induces a third order, A-stable, error inhibiting scheme which is shown to be particularly effective.

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