激波与轻质气柱作用过程的磁场抑制特性  

Magnetic field suppression characteristics in interaction process between shock wave and light gas cylinder

作　　者：张升博 张焕好[1] 张军[2] 毛勇建[2] 陈志华[1] 石启陈 郑纯 Zhang Sheng-Bo;Zhang Huan-Hao;Zhang Jun;Mao Yong-Jian;Chen Zhi-Hua;Shi Qi-Chen;Zheng Chun(National Key Laboratory of Transient Physics,Nanjing University of Science&Technology,Nanjing 210094,China;Institute of Systems Engineering,China Academy of Engineering Physics,Mianyang 621999,China;School of Energy and Power Engineering,Nanjing University of Science&Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学,瞬态物理全国重点实验室,南京210094 [2]中国工程物理研究院,总体工程研究所,绵阳621999 [3]南京理工大学,能源与动力学院,南京210094

出　　处：《物理学报》2024年第8期195-208,共14页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12072162,12102196,12072334);江苏省自然科学基金(批准号:BK20210322);中国博士后科学基金(批准号:2022M711642)资助的课题.

摘　　要：本文采用CTU(corner transport upwind)+CT(constrained transport)算法求解理想可压缩磁流体动力学(magneto-hydro-dynamic,MHD)方程,仿真研究了不同方向磁场控制下高斯分布轻质气柱界面受平面冲击波扰动后的演化过程,揭示了磁场方向对界面不稳定性的影响机理.仿真结果探讨了有/无磁场作用下流场特性与波系结构的发展,对比分析了磁场方向对气柱的长度、高度、射流宽度和体积压缩率的影响,并结合流场上半区环量、能量分量、速度和磁场力分布,多角度分析了磁场方向对界面不稳定性的影响机理.结果表明,磁压力推动涡量远离界面,降低了涡量在密度界面上的沉积而附着在分裂后的涡层上,从而有效抑制Richtmyer-Meshkov不稳定性对界面的影响;由于磁张力附着在被分离的涡层上,且其作用方向与界面因速度剪切而卷起涡的方向相反,因此抑制了界面因Kelvin-Helmholtz不稳定性而形成涡串.另外,纵向磁场控制下的磁张力反作用于中轴射流方向,同样抑制了Rayleigh-Taylor不稳定性的发展.Based on ideal compressible magnetohydrodynamics(MHD)equations,the interface instabilities induced by the interaction between planar shock wave and the light gas(Helium)cylinder under the influence of the magnetic fields with different directions are investigated numerically by using the CTU(corner transport upwind)+CT(constrained transport)algorithm.The numerical results elucidate the evolution of flow field characteristics and wave structures with and without magnetic field.Moreover,we examine the influence of the magnetic field direction on a characteristic scales(including the length,height and width of the central axis of gas cylinder),as well as the volume compressibility.Then,the mechanism of the magnetic field direction affecting the interface instability is studied in depth by integrating the analyses of the circulation,energy,velocity and magnetic force distribution within the flow field.The core of this study,is to explore the suppression mechanism of interface instability by magnetic field force.The results show that the magnetic pressure plays a crucial role in driving vorticity away from the interface,thereby reducing its deposition on the density interface.Simultaneously,it adheres to the divided vortex layer,thereby effectively isolating the influence of Richtmyer-Meshkov instability on the interface.On the other hand,the magnetic tension adheres to the separated vortex layer,and its direction is opposite to that of the vorticity generated by the shear of interface velocity.This action effectively suppresses the Kelvin-Helmholtz instability and the rolling-up of vortices on the density interface.Additionally,under the control of a longitudinal magnetic field,the direction of magnetic tension is opposite to the direction of the central jet,effectively suppressing the development of Rayleigh-Taylor instability.

关 键 词：RICHTMYER-MESHKOV 不稳定性 磁流体动力学 激波 高斯界面 

分 类 号：O361.3[理学—流体力学]