在这份报纸,二次的 nonconforming 砖元素(MSLK 元素) 介绍了在[10 ] 被用于 3D 司烧方程。为混合元素对 MSLKP 1 的不稳定性被分析,在珍视向量的 MSLK 元素接近的地方速度和 piecewise P 1 元素接近压力。作为痊愈,我们采用 piecewise P 1 宏元素到 discretize 压力协调而不是长方体上的标准 piecewise P 1 元素。这新对是稳定的,最佳的错误估计被完成。数字例子验证我们的理论分析。
In this paper, the quadratic nonconforming brick element (MSLK element) intro- duced in [10] is used for the 3D Stokes equations. The instability for the mixed element pair MSLK-P1 is analyzed, where the vector-valued MSLK element approximates the velocity and the piecewise P1 element approximates the pressure. As a cure, we adopt the piecewise P1 macroelement to discretize the pressure instead of the standard piecewise P1 element on cuboid meshes. This new pair is stable and the optimal error estimate is achieved. Numerical examples verify our theoretical analysis.