高超声速混合流动的粒子模拟耦合算法

通过采用基于三维非结构网格的子网格技术,对适用于高超声速混合流动的自适应时间步长粒子模拟耦合算法(Improved Hybrid Particle Simulation Method,IHPSM)进行了改进,在保证算法计算效率的同时降低数值误差。通过对三维双曲钝锥外形的数值仿真及与DSMC(Direct Simulation Monte Carlo)计算结果的对比分析,证明改进的IHPSM算法具有较高的计算精度,且能较大幅度提高计算效率。基于改进的IHPSM算法,文中针对双曲钝锥外形进行了稀薄气体效应和飞行马赫数对高超声速流动影响规律的研究。结果表明,气体稀薄程度的增加会减缓双曲钝锥前端流场宏观物理量的变化梯度,使流场激波结构变厚;来流马赫数的增大会使激波明显增强,但对激波厚度与结构的影响较小。

Study on hybrid particle simulation method for hypersonic mixed flows

A hybrid all-particle scheme(Improved Hybrid Particle Simulation Method,IHPSM),which is intended for hyper-sonic mixed rarefied-continuum flows,is extended for improved efficiency and wider applicability by employing the three-dimensional unstructured sub-cell technique.To assess the validity of the improved hybrid particle simulation scheme,a typical test case for three dimensional hyperbolic blunt cone is simulated.The results of IHPSM method for flow field are in good agreement with the standard DSMC results.Notably,the hybrid procedures allow a large reduction in overall simulation expense relative to DSMC.In addition,the relationship between the hypersonic flow field and the rarefied gas or Mach number is studied by simulating a series of test cases of the hyperbolic blunt cone.As the inflow gas becomes rarer,the gradient of the macroscopic properties in front of the hyperbolic blunt cone becomes smaller,and the shock wave is thicker.The increase of Mach number increases the values of the macroscopic proper-ties in the shock wave,but has little influence on the shock wave structure.