单模大扰动的Richtmyer-Meshkov不稳定性

High-amplitude single-mode perturbation evolution of Richtmyer-Meshkov instability

采用高精度的多介质Ghost-Fluid方法,对马赫数为1.15的激波分别作用于单模大扰动Air-CO2、Air-SF6、Air-N2和Air-He界面后的Richtmyer-Meshkov不稳定现象进行了数值研究,得到了不同时刻扰动界面的演化图像,给出了流场的密度等值线和密度纹影图,同实验结果吻合较好。给出了界面的扰动增长随时间变化的情况,并同理论模型进行了对比。对激波从轻气体进入重气体的情况,扰动增长可采用Sadot模型描述线性阶段和早期非线性阶段;对于弱激波同密度接近的气体界面的相互作用,线性阶段时间较长,可用线性模型描述。

The high-amplitude single-mode Richtmyer-Meshkov instability is simulated by using the high-resolution ghost-fluid method. The initial conditions and computational domain are modeled after the single-mode, 1.15-Mach, shock tube experiment by Jourdan G, et al. Four test examples are presented with the evolutions of the air-CO2, air-SF6, air-N2and air-He interfaces, including density and shading contours. The simulated amplitudes are in agreement with the experimental data and the predictions of the theoretical models. The perturbation growths for the light-heavy （air-SF6and air-CO2） cases agree well with the nonlinear model of Sadot O, et al. At the close density （air-N2） interface acting with the weak shock wave, the slow evolution can be described by the linear theory.