激波诱导模型球阵非稳态阻力的数值模拟研究

Numerical Simulation Study on Unsteady Drag Force Acting on Model-Sphere Array Induced by Shock Wave

采用CFD软件,对激波诱导单排四球模型球阵绕流场进行三维数值模拟,在计算模型和方法准确性验 证基础上,分析模型球非稳态阻力的形成机理,并揭示激波马赫数Ms和无量纲间距H对非稳态阻力和激波结构的影响.结果表明：模型球阻力系数Cd曲线存在一个尖锐的最大值波峰和一个波谷的结构,且最终趋于某一稳态正值; Ms越小,Cd峰值越大,谷值越小, Cd曲线波动幅度越大;激波反射、衍射、聚焦和干涉行为共同影响非稳态阻力系数;无量纲间距H越小,相邻球的激波干涉越显著,Cd峰值越大.

In this study,the 3Dnumerical simulation of a gas flow around a four-spheres-in-one-row array induced by shock wave was performed with CFD software.Based on verifying the accuracy of calculation model and method,the formation mechanism of unsteady drag force exerted on a model sphere and the effect of the Mach number M_s of shock wave and the non-dimensional interval distance H on unsteady drag force and shock wave structure were analyzed.The result shows that each curve of the drag coefficient C_d has a sharp maximum value peak and a valley,and finally C_dtends to be a steady-state positive value.Furthermore,the smaller the value of M_sis,the larger the peak value and the fluctuating amplitude of the curve,and the smaller the valley value of C_d.Besides,the combination of shock wave reflection,diffraction,focusing and interference behaviors affects the unsteady drag coefficient.And the smaller the value of His,the more remarkable the shock interference between adjacent spheres,and the larger the peak value of C_d.