arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.06958math.NAcs.NA
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多面体网格上的非协调有限元

Non-conforming finite elements on polytopal meshes

Jerome Droniou, Robert Eymard, Thierry Gallouet, Raphaele Herbin

摘要:

在这项工作中,我们提出了一个通用的框架不符合有限元多面体网格,其特征在于可以是通用多边形/多面体的元素。首先,我们提出的功能框架的例子,一个线性椭圆问题,代表了单相流在多孔介质中。该框架收集了各种可能的非一致性方法,并为这个简单的模型提供了误差估计。然后,我们转向应用程序的功能框架的情况下,一个稳定的退化椭圆型方程,其中需要一个质量集总技术,在这里,这种技术只是包括在使用不同的-分段常数函数重建所选择的自由度。收敛结果表明,这种退化模型。然后,我们介绍了一种新的特定的非一致性方法,被称为局部丰富的多面体非一致性(LEPNC)。这些基函数包括专用于网格的每个面(并且与这些面上的平均值相关联)的函数,以及跨越每个多面体元素中的局部$\mathbb{P}^1$空间的函数。这些基函数的插值性质的分析,并提出了质量集总技术。数值试验,以评估这种方法的效率和精度的各种例子。最后,我们表明,通用的多面体非一致性方法,包括LEPNC,可以插入到梯度离散化方法框架,这使得他们服从所有的误差估计和收敛结果,在这个框架中建立了各种模型。

英文摘要:

In this work we present a generic framework for non-conforming finite elements on polytopal meshes, characterised by elements that can be generic polygons/polyhedra. We first present the functional framework on the example of a linear elliptic problem representing a single-phase flow in porous medium. This framework gathers a wide variety of possible non-conforming methods, and an error estimate is provided for this simple model. We then turn to the application of the functional framework to the case of a steady degenerate elliptic equation, for which a mass-lumping technique is required; here, this technique simply consists in using a different --piecewise constant-- function reconstruction from the chosen degrees of freedom. A convergence result is stated for this degenerate model. Then, we introduce a novel specific non-conforming method, dubbed Locally Enriched Polytopal Non-Conforming (LEPNC). These basis functions comprise functions dedicated to each face of the mesh (and associated with average values on these faces), together with functions spanning the local $\mathbb{P}^1$ space in each polytopal element. The analysis of the interpolation properties of these basis functions is provided, and mass-lumping techniques are presented. Numerical tests are presented to assess the efficiency and the accuracy of this method on various examples. Finally, we show that generic polytopal non-conforming methods, including the LEPNC, can be plugged into the gradient discretization method framework, which makes them amenable to all the error estimates and convergence results that were established in this framework for a variety of models.

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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