预处理法求解定常/非定常混合网格的全速流场  

Using preconditioning method to simulate steady/unsteady flows at all speeds on hybrid grids

作　　者：肖天航[1] 昂海松[1] 余少志[2] 王旭刚[1] 段文博[1] 

机构地区：[1]南京航空航天大学微型飞行器研究中心,江苏南京210016 [2]南京航空航天大学能源与动力学院,江苏南京210016

出　　处：《空气动力学学报》2007年第4期425-430,442,共7页Acta Aerodynamica Sinica

摘　　要：运用时间导数预处理法在混合网格上求解三维定常/非定常N-S方程。预处理后的N-S方程,用二阶迎风格式的有限体积法离散,隐式、LU-SGS迭代求解,双时间步推进求解非定常流。本文以一维预处理欧拉方程为基础进行分析,提出了一种特征变量的边界条件以适应预处理后的特征系统。从极低速到跨声速范围的众多算例表明,本文的边界条件处理稳定有效,预处理法在各种速度下都具备同样快速的收敛性,在较宽的使用范围内均能得到理想的计算结果。A time-derivative preconditioning algorithm is implemented to solve three-dimensional steady/unsteady Navier-Stokes equations on hybrid grids. The preconditioned Navier-Stokes equations are discretized by an implicit secondorder upwind finite-volume scheme and solved by applying LU-SGS method. A dual-time stepping approach extends this algorithm to unsteady flows. In this paper characteristic variable boundary conditions are develoned to suit with thepreconditioned characteristic systems. Resuhs obtained for a wide range of Mach numbers from very low speed flows to transonic flows demonstrate that the preconditioning method ensures same rapid convergence for flows even at very low speed and also indicate that this algorithm provides satisfactory accuracy for a wide range of flow problems.

关 键 词：预处理 N-S方程 双时间步 特征边界条件 混合网格 

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]