一种全速域的计算方法及其应用

A Modified Numerical Method for Arbitrary Mach Number Flows Based on the Preconditioning Technique

针对原可压缩流动求解器不能用于低速不可压缩流动预测的缺点,采用预处理技术对控制方程特征系统、隐式求解方法进行修正,并采用预处理修正的AUSM+-up格式离散对流项.采用修正后的求解器对无粘鼓包流动、顶盖驱动粘性方腔流动以及Laval(拉瓦尔)喷管流动等算例进行数值仿真,并将数值仿真结果与基准解进行对比.结果表明将预处理技术应用于全速域流动问题的求解是可行的,经预处理修正后的求解器能够用于低速、亚音速、跨音速以及超音速流动问题的求解.

The preconditioning technique was applied to modify the existent LU-SGS solver for compressible flows,which was unsuitable for the prediction of low-speed incompressible flows. The preconditioning modification included treatment of the eigen system of the governing equations,improvement of the implicit solving method and discretization of the convection terms with the low-diffusion difference scheme and the AU SM＋-up scheme. The modified solver was applied to numerical simulations of inviscid bump flows,lid-driven square cavity viscous flows and Laval nozzle flows. The comparison between the present results and those in the previous literatures proves the feasibility of the preconditioning-modified numerical method in the simulation of arbitrary Mach number flows,including the low-speed,the subsonic,the transonic and the supersonic invicid or viscous flows.