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arXiv 1605.04085math.NAcs.NA
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高阶非贴合有限元法用于斯托克斯界面问题

Higher order unfitted FEM for Stokes interface problems

TU Wien(维也纳工业大学);WWU Münster(明斯特大学)

Philip Lederer, Carl-Martin Pfeiler, Christoph Wintersteiger, Christoph Lehrenfeld

AI总结:

本文提出一种高阶非贴合有限元方法,用于求解斯托克斯界面问题,通过弱形式实现界面条件,并结合鬼罚项和参数映射提高精度。

摘要:

我们考虑了静止斯托克斯界面问题在速度-压力格式中的离散化。界面以标量函数的零水平面隐式描述,这在基于水平集的方法中很常见。因此,界面不与网格对齐。采用基于泰勒-霍德速度-压力对和XFEM(或CutFEM)修改的非贴合有限元离散化方法来近似解。这允许准确近似具有强或弱间断的解,其中界面不与网格对齐。为了获得一致、稳定和准确的公式,需要几种额外技术。首先,使用Nitsche型公式以弱形式实现界面条件。其次,使用鬼罚稳定化获得稳定的变分公式。最后,为了高精度近似隐式描述的几何,使用分段线性界面重建和底层网格的参数映射。我们介绍了该方法并讨论了数值示例的结果。

英文摘要:

We consider the discretization of a stationary Stokes interface problem in a velocity-pressure formulation. The interface is described implicitly as the zero level of a scalar function as it is common in level set based methods. Hence, the interface is not aligned with the mesh. An unfitted finite element discretization based on a Taylor-Hood velocity-pressure pair and an XFEM (or CutFEM) modification is used for the approximation of the solution. This allows for the accurate approximation of solutions which have strong or weak discontinuities across interfaces which are not aligned with the mesh. To arrive at a consistent, stable and accurate formulation we require several additional techniques. First, a Nitsche-type formulation is used to implement interface conditions in a weak sense. Secondly, we use the ghost penalty stabilization to obtain an inf-sup stable variational formulation. Finally, for the highly accurate approximation of the implicitly described geometry, we use a combination of a piecewise linear interface reconstruction and a parametric mapping of the underlying mesh. We introduce the method and discuss results of numerical examples.

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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