气泡堆积法生成局部加密非结构化网格

Local Refinement of Unstructured Grid by Bubble Packing Method

对生成非结构化网格的气泡堆积法(BPM)进行改进,提出了一种生成局部加密非结构化网格的算法.该算法通过向多边形顶点添加任意大小气泡以及在内部设置点源,并利用反距离加权平均法传递节点信息,简单地实现了局部加密/稀疏网格的生成.同时,还提出了气泡数量的控制方法,可对过于稠密或者疏松的气泡群进行气泡的删除和添加,使所有的气泡更好地与计算区域相匹配,消除了不规则三角形网格的生成,提高了生成网格的质量.用改进的BPM算法对矩形区域生成了边界加密、中心稀疏的非结构化网格,在雷诺数为1 000的工况下对方腔顶盖驱动流进行了数值模拟,与基准解对比非常吻合,证明生成的网格质量较好.

A local refinement method of unstructured grid generated by bubble packing method （BPM） is proposed. In the present method, different size bubbles are added to the real and artificial vertices of the domain nodes of the domain by the and bubble information of these vertices is transferred to the inner Shepard interpolation method. Moreover, a method to control the population of bubbles is presented to add bubbles in large gap between bubbles and remove bubbles to eliminate overlapping so that the generation of skinny triangles is avoided and the grid quality is clearly improved. Furthermore, the improved BPM is applied to generate unstructured grid with local refinement near boundary for square domain to simulate the lid-driven flow in a square cavity with Re= 1 000. The numerical result agrees well with the benchmark solution, indicating that the improved BPM is effective to the computation of fluid flow and heat transfer.