求解Boltzmann模型方程高性能并行算法在航天跨流域空气动力学应用研究  

Study on High Performance Parallel Algorithm for Spacecraft Re-Entry Aerodynamics in the Whole of Flow Regimes Using Boltzmann Model Equation

作　　者：李志辉[1,2] 蒋新宇[1] 吴俊林[1] 徐金秀[3] 白智勇[1] 

机构地区：[1]中国空气动力研究与发展中心超高速空气动力研究所,四川绵阳621000 [2]中国空气动力研究与发展中心空气动力学国家重点实验室,四川绵阳621000 [3]无锡江南计算技术研究所,江苏无锡214083

出　　处：《计算机学报》2016年第9期1801-1811,共11页Chinese Journal of Computers

基　　金：国家杰出青年科学基金(11325212);国家“九七三”重点基础研究发展计划项目(2014CB744100);国家自然科学基金(91130018,91016027,91530319);国家“十二五”国防预研基金(51313030104)资助~~

摘　　要：对Boltzmann方程碰撞积分物理分析与可计算建模,得到适于描述航天再入从外层空间到近地面各流域统一Boltzmann模型方程,提出求解Boltzmann模型方程统一算法高性能并行计算数学模型.发展离散速度空间区域分解大规模并行计算技术,分析统一算法变量依赖关系,建立可扩展并行计算方案;研究数据并行分布与并行执行特征,开展大规模并行化程序设计,并在小、中、大规模256-512、4096-20 625CPU及异构计算机500-45 000、3125-112 500进程并行算法测试,建立稳定运行于国产千万亿次超级计算机高性能可扩展大规模并行算法与航天器再入跨流域复杂气动力/热绕流问题并行化软件应用平台.通过对稀薄流到连续流再入飞行不同高度可回收返回式卫星飞行器、近空间大尺度机动飞行器跨流域绕流环境不同粒度高性能计算与验证,揭示大尺度复杂结构飞行器跨流区飞行稀薄过渡流区热流系数比连续、近连续流区热流系数随物面变化剧烈得多、大得多,发现该类飞行器后端面热流最大值发生在水平舵外侧拐角处,达驻点热流六分之一量级,提供了一个可靠求解航天器再入各流域高超声速绕流问题统一算法高性能并行计算应用研究方向.The unified Boltzmann model equation is presented for describing three-dimensional complex hypersonic flow transport phenomena covering various flow regimes by modeling processing of Boltzmann collision integral. The gas-kinetic numerical schemes of coupling iteration are constructed directly to capture and update the time evolution of the molecular velocity distribution function by using explicit operator splitter, and then the mathematical model of high-performance parallel computation is presented by the surroundings of massive parallel programmer for the Gas-Kinetic Unified Algorithm （GKUA） in solving the Boltzmann model equation. The computing principle of domain decomposition is investigated on the basis of two-phase six-dimensional space of physical space and velocity space, the data-communication expression of the domain decomposition strategy is deduced for the gas-kinetic numerical method, and then the computing technique of parallel domain decomposition in the discrete velocity space is presented. As a result, the gas- kinetic massive parallel algorithm is developed to solve the hypersonic aerothermodynamics from rarefied transition to continuum covering various flow regimes. Based on the parallel program testing and the numerical parallel experiment with different CPU scales of 256-512, 4096-20 625 and numbers of processor cores 500-45 000 and 3125-112 500, it is validated that the present parallel algorithm possesses quite high parallel efficiency and expansibility with good load balance and data communication efficiency. Three-dimensional complex hypersonic aerothermodynamics flows with different Mach numbers and Knudsen numbers past sphere-cone satellite body and complex wing-body assembled vehicle with big scale covering various flow regimes are computed and verified by the massive-scale parallel computation in high-performance computer systems. The computational results are found in high resolution of the flow fields and good agreement with the related DSMC, experimental and theoretical

关 键 词：航天器 跨流域空气动力学 BOLTZMANN模型方程 统一算法 区域分解 高性能并行计算 

分 类 号：TP301[自动化与计算机技术—计算机系统结构]