OpenFoam中多面体网格生成的MPI+OpenMP混合并行方法

Hybrid MPI+OpenMP Parallel Method on Polyhedral Grid Generation in OpenFoam

网格生成是计算流体力学中非常重要的一环,大规模数值模拟过程中对网格精度要求的提高会导致网格生成所耗的时间增加.文中基于OpenFoam开源软件中的网格生成算法,主要研究多面体网格的并行生成,并提出OpenMP和MPI混合并行的多面体网格生成方法.通过理论分析得到,使用混合并行方法生成相同质量的网格时,混合并行方法生成网格的时间消耗随着线程数量和网格单元数量的增加而减少.3组使用不同求解器的数值模拟实验结果表明,该混合并行方法不但可以保证生成网格的质量---可以正常进行数值计算模拟且模拟结果与原方法相比几乎没有差别,而且生成同样质量与数量网格的耗时最多可以缩短至未使用OpenMP并行方法之耗时的1/4以内.

Grid generation is an important step of computational fluid dynamics.In the process of large-scale numerical simulation,the time consumption of grid generation increases with the number of grids which often increases with the simulation accuracy.Based on the grid generation algorithm in an open-source software called OpenFoam,this paper proposes a hybrid parallel me-thod of OpenMP and MPI for polyhedral grid generation.By theoretical analysis,we show that when the hybrid parallel method is used to generate the same quality grids,increasing the number of threads and grid cells will reduce the time consumption of grid generation.Three numerical simulations using different solvers show that the grids generated by the hybrid parallel method and the original method have close qualifications,and the simulation results are almost indistinguishable from those of the original method.Furthermore,the time consumption of this method to generate the same quality and quantity grids can be reduced to less than a quarter of the time consumption without using OpenMP parallel method.