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arXiv 1010.4563math.NAcs.NA
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大波数亥姆霍兹方程的绝对稳定局部间断伽辽金方法

Absolutely stable local discontinuous Galerkin methods for the Helmholtz equation with large wave number

The University of Tennessee(田纳西大学);Oak Ridge National Laboratory(橡树岭国家实验室)

Xiaobing Feng, Yulong Xing

AI总结:

针对高频亥姆霍兹方程,提出两种使用非标准数值通量的局部间断伽辽金方法,证明其对波数和网格尺寸绝对稳定,并在预渐近区给出最优阶误差估计。

摘要:

针对高频区域中带有一阶吸收边界条件的亥姆霍兹方程,发展了两种使用非标准数值通量的局部间断伽辽金(LDG)方法。结果表明,所提出的LDG方法对波数和网格尺寸都是绝对稳定的(因此是适定的)。在预渐近区,对所有波数证明了关于网格尺寸的最优阶误差估计。为了分析所提出的LDG方法,将其重新表述并视为(非协调)混合有限元方法。分析的关键是为每个LDG方法建立广义的inf-sup条件,该条件在没有任何网格约束的情况下成立。广义的inf-sup条件进而容易推导出所提出的LDG方法所需的绝对稳定性。反过来,稳定性结果不仅保证了LDG方法的适定性,而且在误差估计的推导中起着关键作用。文中还给出了数值实验,验证了理论结果并比较了所提出的两种LDG方法。

英文摘要:

Two local discontinuous Galerkin (LDG) methods using some non-standard numerical fluxes are developed for the Helmholtz equation with the first order absorbing boundary condition in the high frequency regime. It is shown that the proposed LDG methods are absolutely stable (hence well-posed) with respect to both the wave number and the mesh size. Optimal order (with respect to the mesh size) error estimates are proved for all wave numbers in the preasymptotic regime. To analyze the proposed LDG methods, they are recasted and treated as (non-conforming) mixed finite element methods. The crux of the analysis is to establish a generalized {\em inf-sup} condition, which holds without any mesh constraint, for each LDG method. The generalized {\em inf-sup} conditions then easily infer the desired absolute stability of the proposed LDG methods. In return, the stability results not only guarantee the well-posedness of the LDG methods but also play a crucial role in the derivation of the error estimates. Numerical experiments, which confirm the theoretical results and compare the proposed two LDG methods, are also presented in the paper.

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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