柱形汇聚几何中内爆驱动金属界面不稳定性

采用自研的高保真度爆轰与冲击动力学程序，对柱形汇聚几何中内爆驱动金属材料界面不稳定性的动力学行为，进行了数值模拟研究。结果表明，首次冲击后至约12 μs，界面发展以RM（Richtmyer-Meshkov）不稳定性为主；12 μs后至冲击波聚心反弹加载前，界面聚心运动处于加速减速状态，界面发展由RT (Rayleigh-Taylor)不稳定性主导；冲击波聚心反弹加载后，界面发展又由RM不稳定性主导。另外，还研究了初始条件（初始振幅、初始波长、钢壳初始厚度和几何构型）对柱形内爆驱动金属材料界面不稳定性的影响。结果显示:初始振幅较大时振幅增长也较大；初始波长较小（模数较大）时振幅增长较小，而且存在一个截止波长；钢壳厚度会抑制扰动增长，也存在一个截止厚度；几何汇聚效应会使扰动增长速度更快。

Numerical investigations of the interface instabilities of metallic material under implosion in cylindrical convergent geometry

In this paper, the dynamical behavior of metal interface instability driven by implosion in cylindrical convergent geometry is numerically investigated by using an in-house high-fidelity detonation and shock wave program. The results indicate that, in the development process of perturbed interface, the RM instability is primary from the initial shock to 12 μs; after 12 μs and before rebound loading of the convergent shock wave, the interface moves towards the center deceleratedly with an increasing acceleration, and the RT instability dominates the evolution of perturbed interface; after the re-shock, the perturbation growth is dominated by the RM instability again. The effects of initial conditions such as the initial amplitude, wavelength (mode number), thickness of steel shell and geometry configuration on the metal interface instability driven by cylindrical implosion are also investigated. It is shown that, the instantaneous amplitude is larger when the initial amplitude is larger; the instantaneous amplitude is smaller when the initial wavelength is smaller, and a cutoff wavelength exists; the larger thickness of steel shell can suppress the perturbation growth, and a cutoff thickness also exists; the geometrical convergent effect causes the perturbation to grow faster.