重叠网格中割补法的改进及应用

Improvement and application of cut-paste method in overset mesh

文章基于割补法的思想,结合物面距优化准则发展了一种改进型洞面优化方法。首先,求出各子网格的物面距,并将背景网格的物面距设置为一个大值;其次,与传统割补法不同,在网格切割的同时比较洞边界点与其贡献单元的物面距大小,当前者的物面距离小于或等于后者时停止洞边界更新,使得洞边界位于物面中间。在网格填补过程中,以切割结束时的洞边界作为初始阵面进行网格回填,直至产生两层插值边界。该方法解决了传统割补法洞边界位置不确定性的问题,同时保持了洞面优化的高效性。另外,在填补过程中不需要再次搜索洞边界点的贡献单元,从而避免了当物面距离很近时因少数洞边界点的寻点失败而导致洞边界进入物面内部的问题。最后通过典型流动算例验证了该方法的准确性与可靠性。

Based on the idea of the cut-paste method, an enhanced hole surface optimization method taking advantage of wall distance optimization principle has been developed. Firstly, the wall distance of each subgrid is calculated, and a large value is set for the wall distance of the background grid. Secondly, unlike the traditional cut-paste method, the wall distance of each fringe point is compared with that of its donor cell during the cut process. The cut process stops when the wall distance of each fringe point is not greater than that of its donor cell so that the hole boundary locates in the middle of different objects. During the paste process, fringe points generated at the end of the cut process are used as the initial front to perform mesh backfilling for the generation of two layers of interpolation boundary. The enhanced method solves the problem of the uncertainty of the boundary position of the traditional cut-paste method, while maintaining the efficiency of the hole surface optimization. In addition, the process of searching donor cells of fringe points is omitted in the paste process, thereby avoiding the problem that fringe points may enter other objects due to the failure of donor cell searching when different objects are very close to each other. Finally, typical numerical examples are given to verify the accuracy and reliability of the enhanced method.