Numerical study on Rayleigh-Taylor effect on cylindrically converging Richtmyer-Meshkov instability
Numerical study on Rayleigh-Taylor effect on cylindrically converging Richtmyer-Meshkov instability
复制标题
圆柱收敛Richtmyer-Meshkov不稳定性的瑞利-泰勒效应数值研究
DOI：
10.1007/s11433-019-9441-4
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Wen Chih-Yung
中科院分区：
文献类型：
--
作者：
Zhai ZhiGang;Zhang Fu;Zhou ZhangBo;Ding JuChun;Wen Chih-Yung
用迎风CE/SE方法数值模拟了柱面收敛条件下二维AIR/SF6单模界面的演化过程。重点研究了流体减速对相变的瑞利-泰勒效应。RTPI是我们在之前的实验中首次观察到的，但其相关机制尚不清楚。通过分离三维效应，发现初始振幅(A0)、方位角振型数(K0)和再激矩是决定RTPI发生的三个主要参数。在(k0，a0)的变量空间中，对于每个k0求出了RTPI发生的临界a0，并且存在一个阈值k0，低于该阈值的RTPI无论如何都不会发生。存在与最大临界0对应的特殊0，且临界0与k0的约化规律可用指数衰减函数来描述。结果表明，RTPI的发生需要一个小于临界值的小冲击时刻，一个大于阈值的大冲击时刻，以及一个晚于RTPI发生的再冲击正确时刻。最后，研究了入射冲击波强度、密度比和界面初始位置对K0阈值和最大临界位置的影响。这些新的发现将有助于理解收敛的Richtmyer-Meshkov不稳定性，并有助于设计惯性约束聚变太空舱的最佳结构。
Evolution of a two-dimensional air/SF6single-mode interface is numerically investigated by an upwind CE/SE method under a cylindrically converging circumstance. The Rayleigh-Taylor effect caused by the flow deceleration on the phase inversion (RTPI) is highlighted. The RTPI was firstly observed in our previous experiment, but the related mechanism remains unclear. By isolating the three-dimensional effect, it is found here that the initial amplitude (a0), the azimuthal mode number (k0) and the re-shocking moment are the three major parameters which determine the RTPI occurrence. In the variable space of (k0,a0), a criticala0 for the RTPI occurrence is solved for eachk0, and there exists a threshold value ofk0below which the RTPI will not occur no matter whata0is. There exists a specialk0corresponding to the largest criticala0, and the reduction rule of criticala0withk0can be well described by an exponential decay function. The results show that the occurrence of the RTPI requires a smalla0which should be less than a critical value, a largek0which should exceed a threshold, and a right impinging moment of the re-shock which should be later than the RTPI occurrence. Finally, the effects of the incident shock strength, the density ratio and the initial position of the interface on the threshold value ofk0and on the maximum criticala0are examined. These new findings would facilitate the understanding of the converging Richtmyer-Meshkov instability and would be helpful for designing an optimal structure of the inertia confinement fusion capsule.