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arXiv 2003.06489math.NAcs.NA
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一类nonlinear elliptic偏微分方程的截断有限元误差估计

Cut finite element error estimates for a class of nonlinear elliptic PDEs

Georgios Katsouleas, Efthymios N. Karatzas, Fotios Travlopanos

摘要:

虚拟域方法的动机是在复杂域中的许多应用,其边界暴露于大的拓扑变化或变形,虚拟域方法将感兴趣的实际域嵌入到固定的笛卡尔背景中。这通常通过水平集函数对其边界进行几何参数化来实现。本文将非拟合割元数值格式的先验分析推广到线性问题之外。更确切地说,我们考虑了半线性椭圆边值问题的形式$- Δu +f_1(u)=f_2$多项式非线性通过切割有限元法的离散。边界条件是强制执行的,使用Nitsch型的方法。为了确保稳定性和误差估计,是独立的边界相对于网格的位置,配方增加了额外的边界区鬼惩罚条款。这些项作用于与剪切元素相关联的面处的法向梯度的跳跃。先验误差估计的推导,而数值例子说明了该方法的实施和验证的理论研究结果。

英文摘要:

Motivated by many applications in complex domains with boundaries exposed to large topological changes or deformations, fictitious domain methods regard the actual domain of interest as being embedded in a fixed Cartesian background. This is usually achieved via a geometric parameterization of its boundary via level-set functions. In this note, the a priori analysis of unfitted numerical schemes with cut elements is extended beyond the realm of linear problems. More precisely, we consider the discretization of semilinear elliptic boundary value problems of the form $- Δu +f_1(u)=f_2$ with polynomial nonlinearity via the cut finite element method. Boundary conditions are enforced, using a Nitsche-type approach. To ensure stability and error estimates that are independent of the position of the boundary with respect to the mesh, the formulations are augmented with additional boundary zone ghost penalty terms. These terms act on the jumps of the normal gradients at faces associated with cut elements. A-priori error estimates are derived, while numerical examples illustrate the implementation of the method and validate the theoretical findings.

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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