论文标题

$ hp $ -fem的vavenumber-strapic融合,用于全空间异质Helmholtz方程,具有光滑系数

Wavenumber-explicit convergence of the $hp$-FEM for the full-space heterogeneous Helmholtz equation with smooth coefficients

论文作者

Lafontaine, David, Spence, Euan A., Wunsch, Jared

论文摘要

$ HP $ -FEM的收敛理论应用于各种恒定的Helmholtz问题,在论文中率先[Melenk-Sauter,2010],[Melenk-Sauter,2011],[Esterhazy-Melenk,2012],[Melenk-Parsania-Sauter,2013年],2013年]。该理论表明,如果解决方案运算符在波数$ k $中是多项式界定的,那么Galerkin方法是quasioptimal的,前提是$ hk/p \ leq c_1 $和$ p \ geq c_2 \ log k $,其中$ c_1 $很小,$ c_2 $,$ c_2 $,$ c_2 $ andife offore $ $ $ $ $ k.该结果的意义是,如果$ hk/p = c_1 $和$ p = c_2 \ log k $,则可以实现准timimation,而自由度的总数与$ k^d $成正比;即,$ HP $ -FEM不会遭受污染效应。本文证明了异质(即可变效率)Helmholtz方程的类似准timigation结果,它以$ \ Mathbb {r}^d $,$ d = 2,3 $呈现,带有sommerfeld Infinity和$ c^\ infty $ ceefficients。在平面波散射问题的特定情况下,我们还证明了Galerkin解决方案的相对误差的束缚。这些是用于helmholtz方程的$ hp $ -FEM的波数义相互收敛的第一个结果,具有可变系数。

A convergence theory for the $hp$-FEM applied to a variety of constant-coefficient Helmholtz problems was pioneered in the papers [Melenk-Sauter, 2010], [Melenk-Sauter, 2011], [Esterhazy-Melenk, 2012], [Melenk-Parsania-Sauter, 2013]. This theory shows that, if the solution operator is bounded polynomially in the wavenumber $k$, then the Galerkin method is quasioptimal provided that $hk/p \leq C_1$ and $p\geq C_2 \log k$, where $C_1$ is sufficiently small, $C_2$ is sufficiently large, and both are independent of $k,h,$ and $p$. The significance of this result is that if $hk/p= C_1$ and $p=C_2\log k$, then quasioptimality is achieved with the total number of degrees of freedom proportional to $k^d$; i.e., the $hp$-FEM does not suffer from the pollution effect. This paper proves the analogous quasioptimality result for the heterogeneous (i.e. variable-coefficient) Helmholtz equation, posed in $\mathbb{R}^d$, $d=2,3$, with the Sommerfeld radiation condition at infinity, and $C^\infty$ coefficients. We also prove a bound on the relative error of the Galerkin solution in the particular case of the plane-wave scattering problem. These are the first ever results on the wavenumber-explicit convergence of the $hp$-FEM for the Helmholtz equation with variable coefficients.

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