内爆加载下界面不稳定性和湍流混合数值模拟研究  

Numerical investigations of interface instability and turbulent mixing driven by implosion

作　　者：王涛[1,2] 汪兵[1] 林健宇 钟敏[1] 柏劲松[1] 李平[1] 陶钢[2] WANG Tao;WANG Bing;LIN JianYu;ZHONG Min;BAI JingSong;LI Ping;TAO Gang(Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,China;School of Energy and Power Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]中国工程物理研究院流体物理研究所,绵阳621999 [2]南京理工大学能源与动力工程学院,南京210094

出　　处：《中国科学：物理学、力学、天文学》2020年第10期36-47,共12页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：科学挑战专题(编号:TZ2016001);国家自然科学基金(编号:11702272,11532012,11932018)资助项目。

摘　　要：本文采用可压缩多介质黏性流动和湍流数值模拟代码MVFT,研究了球形汇聚几何中内爆加载Air/SF6扰动界面导致的界面不稳定性和湍流混合的演化规律和物理机制.结果表明,这种条件下会发生复杂的波系演化,进而导致界面不稳定性和湍流混合也具有复杂的演化规律.冲击波首次加载Air/SF6扰动界面后诱发Richtmyer-Meshkov(RM)不稳定性;然后扰动界面向心加速运动,此时会发生Rayleigh-Taylor(RT)不稳定性;接着扰动界面逐渐转为向心减速运动,此时发生SF6加速Air的致稳效应,它会抑制界面不稳定性和湍流混合的发展,使湍流混合区(TMZ)宽度增长速度逐渐减小,当RT致稳机制逐渐增强并占绝对主导时,湍流混合区宽度出现负增长.当透射冲击波聚心反弹后,对湍流混合区形成的是一个准等熵斜波-冲击波-泰勒波的二次加载过程,沿重/轻介质方向产生的是加载-加载-卸载效应.准等熵斜波加载也会对RT致稳机制有贡献.反射冲击波加载又会诱发RM不稳定性,而泰勒波加载会诱发RT不稳定性,二次加载产生的反射波聚心又反弹,进而重复准等熵斜波-冲击波-泰勒波的加载过程.汇聚几何所特有的Bell-Plesset(BP)效应会促进界面不稳定性和湍流混合发展.在球形汇聚几何中内爆加载所诱发的界面不稳定性和湍流混合发展过程中,RM不稳定性、RT不稳定性、BP效应和RT致稳机制存在互相竞争机制.湍动能分布显示湍流混合区发展沿径向是不对称的,不同方向湍动能分量和能谱结果表明湍流混合区发展还具有强的各向异性.The interface instability and turbulent mixing of perturbed Air/SF6 interface driven by implosion in spherical convergent geometry are numerically investigated by the use of in-house compressible hydrodynamic code(multi-viscous flow and turbulence).The results revealed the complex evolving laws and physical mechanisms of interface instability and turbulent mixing due to the evolution of complex waves in this case.The RM instability is induced when the perturbed Air/SF6 interface is driven by the incident shock wave.And the perturbed interface accelerates toward the center,thereafter RT instability occurs.Then the perturbed interface slows down and decelerates towards the center,and the RT stabilization appears and suppresses the development of the interface instability and turbulent mixing.When the RT stabilization acts an absolutely dominant role,the growth of the turbulent mixing zone(TMZ)width is restrained completely,and its width in turn reduces.After the rebound of transmitted shock waves,the secondary loading from heavy fluid to light fluid is a combination of quasi-isentropic ramp wave,shock wave and Taylor wave in time series.The loading of quasi-isentropic ramp wave also contributes to the RT stabilization mechanism,the drive of rebound shock wave was seen to have induced the RM instability too,and the impact of Taylor wave resulted in RT instability once again.In the following,the reflected wave moves toward the center and bounces,the third loading process is the same as the secondary one;the TMZ width repeats the same growth laws.The Bell-Plesset(BP)effect which belongs to the conergent geometry can promote the development of TMZ.In the spherical converegent geometry,the competition mechanism among the RM instability,RT instability,BP effect and RT stabilization controls the evolution of interface instability and turbulent mixing.The distributions of turbulent kinetic energy indicate that TMZ evolves asymmetrically along the radial direction.The distributions of three direction components of turbulent

关 键 词：内爆 界面不稳定性 湍流混合 RT致稳 各向异性 

分 类 号：O357.5[理学—流体力学] O354.5[理学—力学]