导弹尾部燃气冲击射流的流场特性仿真研究

摘要

The gas impinging jet has complex wave structures,which is an important fluid mechanics problem in the design of aerospace and weapons.The difficulty of flow-field characteristics research lies in developing a numerical simulation method which has high resolution,also captures shock well.To study the flow-field characteristics of under expanded unsteady-state gas impinging jet,a numerical simulation of under expanded unsteady-state gas impinging jet is carried out using positive schemes method,which discretizes axisymmetric compressible Euler equations.The computation results indicate that the method can capture the complex wave structures due to the impingement jet flow fields including bowed shock waves,Mach reflected wave and the triple point.A comparison of the primary flow characters shows that agreement between the numerical result and experimental measurement is satisfactory.No numerical oscillation occurs near discontinuous points,which shows that positive schemes can capture the shocks well.A new method for this flow numerical study is presented.%燃气冲击流场波系结构复杂,是航空航天和武器系统设计阶段需解决的重要流体力学问题,发展分辨率高、具有强激波捕捉能力的数值方法是研究其流场特性的主要难点.为研究弹尾欠膨胀燃气冲击流场特性,采用正格式方法对轴对称可压缩Euler方程组进行数值离散,并对弹尾欠膨胀非稳态燃气冲击射流进行了数值计算.计算结果表明,正格式方法能够较好地捕捉到燃气冲击射流在流场演化过程中所形成的曲面激波、马赫反射和三波点等复杂波系结构,数值结果与实验照片反映的主要流动特征的吻合程度是令人满意的,在间断处不会出现数值振荡.这表明所用该方法对间断解具有较强的捕捉能力,为此类流动的数值研究提供了一种新的方法.