湍流模拟壁面距离MPI/OpenMP混合并行计算方法  

MPI/OpenMP hybrid parallel computation of wall distance for turbulence flow simulations

作　　者：赵钟[1] 何磊[1] 张健[1] 徐庆新[1] 张来平[1] ZHAO Zhong;HE Lei;ZHANG Jian;XU Qingxin;ZHANG Laiping(Computational Aerodynamics Institute of China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]中国空气动力研究与发展中心计算空气动力研究所

出　　处：《空气动力学学报》2019年第6期883-892,共10页Acta Aerodynamica Sinica

基　　金：国家重点研发计划（2016YFB0200701）;国家自然科学基金（11532016,91530325）

摘　　要：针对计算流体力学在湍流数值模拟过程中壁面距离计算效率不高的问题,设计了一种基于ADT数据结构搜索的MPI/OpenMP混合并行计算方法,以大幅提高大规模网格壁面距离的计算效率,降低因内存消耗而对网格规模的限制。首先分析了壁面距离计算精度对湍流模拟的重要性,介绍了壁面距离计算的几何基础。随后基于区域分解思想,将计算域划分为不同的子分区,服务器进程收集全局壁面面元网格信息后发送给其他所有进程,各进程根据全局壁面信息,基于ADT数据结构搜索其网格分区内的单元,精确计算壁面距离。为了解决全局壁面信息内存过大的问题,采用MPI/OpenMP混合并行算法,使得各计算节点中仅有一个或少数几个壁面信息备份,这些壁面信息备份被节点内的其他各进程所共享。最后采用大规模网格进行了壁面距离计算测试,网格规模最大达到33.2亿,结果表明,该方法的计算精度和直接搜索法一致,内存耗费下降70%,计算时间减少约1个量级,能满足大规模CFD数值模拟的需求。A parallel wall distance computing approach is proposed for large scale CFD turbulence flow simulations to reduce the wall distance computing time consumption.This method is based on MPI/OpenMP hybrid parallel ADT searching procedure to further improve the computational efficiency and to reduce memory consumption.Firstly,the influence of the accuracy of wall distance computing is analyzed,and the foundational computational geometry algorithm used in this paper is introduced.Then the parallel wall distance computing approach based on the ADT searching procedure is discussed in details.In this method,the total computational field is divided into a number of zones firstly,and then the whole surface faces data on the solid wall is collected and broadcasted to all other processors using MPI communications.The wall distances of spatial cells in each zone are computed based on the ADT searching within each processor.In order to overcome the memory limitation,a MPI/OpenMP hybrid parallel method is proposed,and then only one or a few copies of the surface faces data are created within each computer node other than for each processor.Numerical results show that the present method substantially improves efficiency by one order and reduces the memory consumption by 70%,which indicates that this method can fullfill the demand of large-scale parallel simulations.

关 键 词：湍流壁面距离 ADT搜索 大规模并行计算 风雷软件 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]