二维横向喷流的N-S方程数值解

THE NUMERICAL NAVIER-STOKES SOLUTION OF TWO-DIMENSIONAL FLOW WITH TRANSVERSE INJECTION

关键词:  射流  超音速流  分离  流场  数值解

Key words:  Jet flow  Supersonic flow  Separation  Flow field  Numerical solution

摘要:

让一股射流横向注入超音速流产生所需要的干扰效应是一种飞行器飞行控制的常用手段,如航天飞机和机动导弹上的反作用控制系统(RCS).所以,对射流与主流相互干扰的某些流动特性应该有个基本的了解.本文通过应用MacCormack显格式和Baldwin-Lomax修正的代数湍流模型求解二维RANS方程对带横向射流的绕后台阶的M_∞为2.19和6.00的超音速外干扰流场进行了数值计算.与无喷射流的情形相比,回流涡旋区由2个增加到4个,且底部压力有大的回升,喷口宽度越大,回升效应越显著.另外,数值计算表明,在压力梯度变化比较平缓的区域附加一四阶人工粘性能有效地抑制数值振荡,加快收敛.

Abstract:

Issuing a jet stream into a supersonic external flow is a common technique for flight control of aerospace vehicles. In this paper, MacCormack explicit scheme and Baldwin-Lomax algebraic turbulent model are employed to solve the 2D compressible RANS equations for the numerical simulation of the supersonic and hypersonic external flow over a rearward facing step with transverse injection. The velocity vector field, pressure contour of the field are given for understanding of the interaction phenomina and comparison. The interaction effects increase with the width of slot, but are insensitive to the Mach number of free stream. Adding the fourth-difference dissipation to a central difference scheme in no shock regions can promote the convergence rate and is necessary for the hypersonic problem with transverse injection. The obtained results may be used for the preliminary design of maneuver missiles.