突扩流动主流偏转特性数值模拟研究

以流函数方程作为控制方程,与N-S方程相比,不出现压强项和速度项,与涡量-流函数型N-S方程相比,没有涡量项和速度项,只有流函数项,避免了涡量边界条件问题,将控制方程中未知数的个数变为一个,通过解得流函数而得到其他各项。考虑对流项迎风性质,采用迎风差分格式,对突扩层流进行数值模拟,与DurstF流动试验及混合有限分析法模拟结果比较,基本吻合。通过一系列计算,得出主流经突扩断面偏转后相关特征值与雷诺数Re的关系,扩展了突扩流动的研究内容。

Numerical simulation for deflexion features of sudden expansion laminar in main flow

The Navier-Stokes (N-S) equation with stream function formulation is used as the governing equation.It has no pressure terms or velocity terms compared with the N-S equations,and no vorticity terms or velocity terms compared with the wrticity-stream function equations,awiding the problems of wrticity boundary conditions.The variable is only the stream function term.Considering the upwindfeature of convective term,the upwind scheme is adopted to simulate the 2-D sudden expansion laminar.The results are basically consistent with the experiment results of the Durst and Hybrid Fnnite Analytic Method.On the basic of series of calculations,it establishes the relation between the characteristic value and the Reynolds number, when the main flow deflects after sudden expansion section.This complements the researches on sudden expansion flow.