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arXiv 1302.3076math.NAcs.NA
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非结构化三角网格上的任意拉格朗日-欧拉单步WENO有限体积格式

Arbitrary-Lagrangian-Eulerian One-Step WENO Finite Volume Schemes on Unstructured Triangular Meshes

University of Trento(特伦托大学)

Walter Boscheri, Michael Dumbser

AI总结:

针对移动非结构化三角网格上的非线性双曲守恒律系统,提出一类基于WENO重构和时空伽辽金预测器的高阶精度任意拉格朗日-欧拉单步有限体积格式。

摘要:

本文提出了一类新的高阶精度任意拉格朗日-欧拉(ALE)单步WENO有限体积格式,用于求解移动二维非结构化三角网格上的非线性双曲守恒律系统。采用WENO重构算法实现空间高阶精度,并通过局部时空伽辽金预测器实现高阶单步时间离散。为此,在移动时空单元上采用了控制偏微分方程的新单元局部弱形式。时空基函数和测试函数通过拉格朗日插值多项式获得,这些多项式经过一组预定义节点。此外,使用与PDE弱解相同的局部时空基函数定义的多项式映射,将移动的物理时空单元映射到时空参考单元。为保持算法简单性,最终的ALE单步有限体积格式使用具有直边的移动三角网格。这在ALE框架中是可行的,允许局部网格速度不同于局部流体速度。我们给出了本文提出的格式在空间和时间上高达六阶精度的数值收敛率,并展示了二维可压缩气体动力学欧拉方程的一些经典数值测试问题。

英文摘要:

In this article we present a new class of high order accurate Arbitrary-Eulerian-Lagrangian (ALE) one-step WENO finite volume schemes for solving nonlinear hyperbolic systems of conservation laws on moving two dimensional unstructured triangular meshes. A WENO reconstruction algorithm is used to achieve high order accuracy in space and a high order one-step time discretization is achieved by using the local space-time Galerkin predictor. For that purpose, a new element--local weak formulation of the governing PDE is adopted on moving space--time elements. The space-time basis and test functions are obtained considering Lagrange interpolation polynomials passing through a predefined set of nodes. Moreover, a polynomial mapping defined by the same local space-time basis functions as the weak solution of the PDE is used to map the moving physical space-time element onto a space-time reference element. To maintain algorithmic simplicity, the final ALE one-step finite volume scheme uses moving triangular meshes with straight edges. This is possible in the ALE framework, which allows a local mesh velocity that is different from the local fluid velocity. We present numerical convergence rates for the schemes presented in this paper up to sixth order of accuracy in space and time and show some classical numerical test problems for the two-dimensional Euler equations of compressible gas dynamics.

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