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arXiv 1611.03368math.NAcs.NA
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非等温可压缩流体在管道中的混合变分离散

A mixed variational discretization for non-isothermal compressible flow in pipelines

TU Darmstadt(达姆施塔特工业大学)

Herbert Egger

AI总结:

本文提出了一种非等温可压缩流体在管道中流动的混合变分离散方法,通过变分原理直接编码质量、能量和熵的守恒,采用混合有限元方法进行空间近似,并通过隐式时间步进方案保证质量守恒和能量耗散,同时允许扩展到更一般的边界条件和流动模型。

摘要:

我们考虑非等温条件下可压缩流体在管道中的流动。从完整的欧拉方程出发,我们提出了一种变分特征化,以非常直接的方式编码质量、能量和熵的守恒。这种变分原理适用于空间中的符合伽辽金近似,自动继承基本物理守恒定律。三种不同的空间用于近似密度、质量流率和温度,并考虑混合有限元方法作为合适的近似空间之一。我们还研究了后续的时间离散化,通过问题适应的隐式时间步进方案,证明了质量的精确守恒以及能量的轻微耗散和熵的增加,这些是由于隐式时间离散化的数值耗散所致。我们分析的主要论点较为一般,允许我们通过少量修改将该方法扩展到更一般的边界条件和流动模型,考虑摩擦、粘度、热传导和与周围介质的热交换。

英文摘要:

We consider the non-isothermal flow of a compressible fluid through pipes. Starting from the full set of Euler equations, we propose a variational characterization of solutions that encodes the conservation of mass, energy, and entropy in a very direct manner. This variational principle is suitable for a conforming Galerkin approximation in space which automatically inherits the basic physical conservation laws. Three different spaces are used for approximation of density, mass flux, and temperature, and we consider a mixed finite element method as one possible choice of suitable approximation spaces. We also investigate the subsequent discretization in time by a problem adapted implicit time stepping scheme for which exact conservation of mass as well as a slight dissipation of energy and increase of entropy are proven which are due to the numerical dissipation of the implicit time discretization. The main arguments of our analysis are rather general and allow us to extend the approach with minor modification to more general boundary conditions and flow models taking into account friction, viscosity, heat conduction, and heat exchange with the surrounding medium.

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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