新型重叠网格洞面优化方法及其应用

高度自动化的洞面优化方法是重叠网格关键技术之一。通过对割补法的分析,针对其洞面切割后洞边界位置不确定性及不可预知性问题,提出将其与物面距离优化准则相结合的新型混合洞面优化方法。该方法针对各物体间体网格,采用物面距离优化准则,将洞边界位置控制在物体中间的位置,使重叠区域更合理、可预测;针对背景网格,将其物面距离设置为较大值,采用物面距离优化准则将其落入物体网格内部的单元一并挖去;针对物面处重叠的网格,采用割补法对其进行切割和填补,保证物面及近壁面网格得以有效的重叠。该方法在保证高适用性的前提下提高了网格重叠质量,自动化程度高,无需人工干预。3个典型复杂流动算例计算结果与实验结果吻合良好,网格重叠区域流场变量传递正确,等值线过渡光滑,流场刻画准确,证明该方法准确可靠。

Novel overlapping optimization algorithm of overlapping grid and its applications

Highly automated overlapping optimization algorithm plays an important role in the overlapping grid. In view of the fact that the result of grids optimized by cut-paste algorithm is not determined and predictable, a new mixed overlapping optimization algorithm is presented which combines the distance optimization principle with the cut-paste algorithm. The distance optimization principle has been adopted to deal with the grids between objects. Hence the fringe boundary layers will be located at the field between objects to make the location of overlapping area better and more predictable. By maximizing the distance value for background grid, we cut the background grids which fall into the grids of other objects. Meanwhile the cut-paste algorithm is employed to optimize the grids, which are overlappingped near or on the wall. The new mixed algorithm improves the quality of overlapping and it is totally automatic. With the enhanced algorithm, three typical aerodynamic cases are performed and excellent agreement of computational results compared with experimental data has been achieved. Moreover, the flow variables at the overlapping zone are transferred accurately, the contour has smooth transition to different grids and the flow describes accurately. The enhanced algorithm shows greater accuracy and practicality than the previous methods.