Improvements on overlapping unstructured grids

Improvements on the efficiency of overlapping unstructured grids have been done in several ways. First of all, the traditional hole mapping method was improved to save physical memories. Then, the wall distance calculation was greatly accelerated by taking advantage of neighbor-to-neighbor searching technique. Besides, extra enhancements have been done to the process of donor cell search for a better performance. During hole cutting, for Cartesian grids generated to approximate the wall surface, just those intersecting with the wall surface were detected and stored. Relative positions of those stored Cartesian cells were used to determine which nodes are inside the wall. Fringe nodes served as the initial front to iteratively optimize the overlapping area with the wall distance criterion. The improved overlapping technique featured in less physical memory occupation, higher efficiency of wall distance calculation, and faster donor cell search. Last but not least, three typical flow examples demonstrated the efficiency of the method developed in the work.