arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1908.05374math.NAcs.NA
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线性抛物型方程高阶有限元逼近的显式龙格-库塔法的稳定性

Stability of explicit Runge-Kutta methods for high order finite element approximation of linear parabolic equations

Weizhang Huang, Lennard Kamenski, Jens Lang

摘要:

研究了线性抛物型方程高阶Lagrange有限元逼近的显式龙格-库塔法的稳定性,建立了确定最大允许时间步长的系统矩阵的最大特征值的界.的刚度和质量矩阵的对角线条目的比率表示的约束被证明是紧在一个小的因素,这只取决于尺寸和选择的参考元素和基函数,但独立的网格或系数的初边值问题正在考虑中。另一个界限,这是不太紧,并表示在网格几何形状,仅取决于网格元素的数量和网格与扩散矩阵的对齐。结果提供了一个洞察网格几何形状和扩散矩阵之间的相互作用如何影响显式积分格式的稳定性时,适用于一般非均匀网格上的线性抛物型方程的高阶有限元逼近。

英文摘要:

We study the stability of explicit Runge-Kutta methods for high order Lagrangian finite element approximation of linear parabolic equations and establish bounds on the largest eigenvalue of the system matrix which determines the largest permissible time step. A bound expressed in terms of the ratio of the diagonal entries of the stiffness and mass matrices is shown to be tight within a small factor which depends only on the dimension and the choice of the reference element and basis functions but is independent of the mesh or the coefficients of the initial-boundary value problem under consideration. Another bound, which is less tight and expressed in terms of mesh geometry, depends only on the number of mesh elements and the alignment of the mesh with the diffusion matrix. The results provide an insight into how the interplay between the mesh geometry and the diffusion matrix affects the stability of explicit integration schemes when applied to a high order finite element approximation of linear parabolic equations on general nonuniform meshes.

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