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arXiv 1111.1167math.NAcs.NAmath-phmath.MP
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任意界面上间断系数椭圆问题的二阶多重网格方法,I:一维问题

Second Order Multigrid Methods for Elliptic Problems with Discontinuous Coefficients on an Arbitrary Interface, I: One Dimensional Problems

Università di Catania(卡塔尼亚大学)

Armando Coco, Giovanni Russo

AI总结:

本文针对任意界面上具有间断系数的椭圆问题,提出一种基于鬼点法和多域公式的一维二阶精度方法,并采用多重网格加速收敛,数值实验验证了二阶精度。

摘要:

本文提出了一种一维二阶精度方法,用于求解任意界面上具有间断系数的椭圆方程,同时一阶导数也达到二阶精度。该方法基于鬼点法,利用合适的界面条件定义鬼点上的值。采用多域公式,将问题分解为两个子问题,并通过界面条件封闭问题。界面条件与内部方程一起松弛,形成对所有网格值(内部点和鬼点)的迭代方法。提供了多重网格方法,并定义了合适的限制算子。对两个子问题分别进行缺陷限制,得到的收敛因子接近于光滑系数情况下的测量值,且与系数跳跃幅度无关。数值测试证实了二阶精度。虽然该方法在一维中提出,但高维扩展正在进行中。

英文摘要:

In this paper we present a one dimensional second order accurate method to solve Elliptic equations with discontinuous coefficients on an arbitrary interface. Second order accuracy for the first derivative is obtained as well. The method is based on the Ghost Fluid Method, making use of ghost points on which the value is defined by suitable interface conditions. The multi-domain formulation is adopted, where the problem is split in two sub-problems and interface conditions will be enforced to close the problem. Interface conditions are relaxed together with the internal equations, leading to an iterative method on all the set of grid values (inside points and ghost points). A multigrid approach with a suitable definition of the restriction operator is provided. The restriction of the defect is performed separately for both sub-problems, providing a convergence factor close to the one measured in the case of smooth coefficient and independent on the magnitude of the jump in the coefficient. Numerical tests will confirm the second order accuracy. Although the method is proposed in one dimension, the extension in higher dimension is currently underway.

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