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arXiv 1905.03390math.NAcs.NA
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辐射传输方程的正向渐近保持近似

Positive asymptotic preserving approximation of the radiation transport equation

Texas A&M University(德克萨斯农工大学)

Jean-Luc Guermond, Bojan Popov, Jean Ragusa

AI总结:

本文提出了一种线性正向且渐近保持的方法来求解单组辐射传输方程,该方法在空间离散中不依赖特定格式,具有空间一阶精度,并在扩散极限下表现出更高的收敛性,同时避免了在光学薄和光学厚区域界面处的振荡问题。

摘要:

我们介绍了一种(线性)正向且渐近保持的方法,用于求解单组辐射传输方程。空间近似是无关离散化的:空间近似可以使用连续或不连续有限元(或有限体积、有限差分)。该方法在空间上是一阶准确的。这种精度与Godunov定理一致,因为该方法是线性的。论文的两个关键理论结果是定理4.4和定理4.8。该方法通过连续有限元进行示例说明。在制造解上,它以$\calO(h)$的速率收敛于$L^2$-范数,在扩散极限下为$\calO(h^2)$。与其它标准技术不同,所提出的方法在光学薄和光学厚区域的界面处不产生振荡。

英文摘要:

We introduce a (linear) positive and asymptotic preserving method or solving the one-group radiation transport equation. The approximation in space is discretization agnostic: the space approximation can be done with continuous or discontinuous finite elements (or finite volumes, or finite differences). The method is first-order accurate in space. This type of accuracy is coherent with Godunov's theorem since the method is linear. The two key theoretical results of the paper are Theorem~4.4 and Theorem~4.8. The method is illustrated with continuous finite elements. It is observed to converge with the rate $\calO(h)$ in the $L^2$-norm on manufactured solutions, and it is $\calO(h^2)$ in the diffusion regime. Unlike other standard techniques, the proposed method does not suffer from overshoots at the interfaces of optically thin and optically thick regions.

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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