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不同磁场构型下Richtmyer-Meshkov不稳定性的数值研究及动态模态分解

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物理学报 2019年第16期68卷 262-272页

作者：董国丹郭则庆秦建华张焕好姜孝海陈志华沙莎南京理工大学瞬态物理国家重点实验室南京210094 City College of New York The City University of New York New York 10031 USA 北京电子工程总体研究所北京100854

基于磁流体动力学,本文通过数值模拟对不同磁场构型下轻质气柱界面Richtmyer-Meshkov不稳定性的演化过程进行了研究.结果显示:磁场对波系演化影响甚微,但能抑制界面不稳定性发展,且横向磁场抑制效果更好.无磁场时,界面形成涡串, SF6射... 详细信息

基于磁流体动力学,本文通过数值模拟对不同磁场构型下轻质气柱界面Richtmyer-Meshkov不稳定性的演化过程进行了研究.结果显示:磁场对波系演化影响甚微,但能抑制界面不稳定性发展,且横向磁场抑制效果更好.无磁场时,界面形成涡串, SF6射流穿过下游界面;有磁场时,界面光滑无涡串.其中,横向磁场下界面更光滑, SF6射流不再穿过界面.此外,由于Richtmyer-Meshkov不稳定性的作用,磁力线在气柱界面发生扭曲,且上游界面处磁力线扭曲程度更大,产生强洛伦兹力,使涡量分层明显;下游界面处,纵向磁场产生的洛伦兹力较横向磁场更小,涡层之间相互干扰.最后,本文将动态模态分解用于界面不稳定性研究,发现:磁场作用下界面仍存在小涡,且纵向磁场下扰动更多.第一模态的稳定涡结构能反映主要流场信息,第二到第四模态下的小涡频率依次增加,且无磁场、纵向和横向磁场的同一模态下,小涡频率依次减小.因而磁场能抑制小涡频率,且横向磁场抑制效果更好.

关键词： Richtmyer-Meshkov 不稳定性磁流体动力学动态模态分解轻质气柱

Numerical study on Rayleigh-Taylor effect on cylindrically converging Richtmyer-Meshkov instability

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Science China(Physics,Mechanics & Astronomy) 2019年第12期62卷 68-77页

作者： ZhiGang Zhai Fu Zhang ZhangBo Zhou JuChun Ding Chih-Yung Wen Department of Modern Mechanics University of Science and Technology of ChinaHefei 230026China Beijing Institute of Space Long March Vehicle Beijing 100076China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

Evolution of a two-dimensional air/SF6 single-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 critical a0 for the RTPI occurrence is solved for each k0, and there exists a threshold value of k0 below which the RTPI will not occur no matter what a0 is. There exists a special k0 corresponding to the largest critical a0, and the reduction rule of critical a0 with k0 can be well described by an exponential decay function. The results show that the occurrence of the RTPI requires a small a0 which should be less than a critical value, a large k0 which 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 of k0 and on the maximum critical a0 are 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.

关键词： converging shock wave Rayleigh-Taylor effect Richtmyer-Meshkov instability

经典Richtmyer-Meshkov不稳定性非线性饱和阈值

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绵阳师范学院学报 2015年第5期34卷 30-33页

作者：刘万海王翔绵阳师范学院计算物理研究中心四川绵阳621000 兰州城市学院甘肃兰州730070

采用小扰动展开法展开到三阶研究了一定压力支撑下的经典流体界面处发生的Richtmyer-Meshkov不稳定性,并按照已有Rayleigh-Taylor不稳定性中非线性饱和阈值的定义,给出了经典平面Richtmyer-Meshkov不稳定性非线性饱和阈值的解析式.研究... 详细信息

采用小扰动展开法展开到三阶研究了一定压力支撑下的经典流体界面处发生的Richtmyer-Meshkov不稳定性,并按照已有Rayleigh-Taylor不稳定性中非线性饱和阈值的定义,给出了经典平面Richtmyer-Meshkov不稳定性非线性饱和阈值的解析式.研究表明,该饱和阈值不仅受到初始扰动波长的影响,还受到初始界面扰动幅值的影响;当不考虑界面扰动幅值效应时,该饱和阈值随初始扰动波长的增加而线性增加;用界面初始扰动波长无量纲后的该饱和阈值大约是0.11,略高于对应Rayleigh-Taylor不稳定性非线性饱和阈值.

关键词： Richtmyer-Meshkov 不稳定性非线性饱和阈值三阶扰动展开

Large-eddy simulations of the Richtmyer-Meshkov instability of rectangular interfaces accelerated by shock waves

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Science China(Physics,Mechanics & Astronomy) 2010年第12期53卷 905-914页

作者： WANG Tao,BAI JingSong,LI Ping & LIU Kun Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621900,China Institute of Fluid Physics China Academy of Engineering Physics Mianyang China

A parallel algorithm and code MVFT(multi-viscous-fluid and turbulence) of large-eddy simulation(LES) is developed from our MVPPM(multi-viscous-fluid piecewise parabolic method),and performed to solve the multi compressible Navier-Stokes(N-S) equations.The effect of the unresolved subgrid-scale(SGS) motions on the large scales is represented by different SGS stress models in LES.A Richtmyer-Meshkov instability experiment of the evolution of a rectangular block of SF6,which occupies half of the height of the shock tube test section,following the interaction with a planar shock wave,is numerically and exhaustively simulated by this code.The comparison between experimental and simulated images of the evolving SF6 block shows that they are consistent.The numerical simulations reproduce the complex developing process of SF6 block,which grows overturningly.The geometric quantities that characterize the extents of SF6 block are also compared in detail between numerical simulations and experiment with good agreements between them,a quantitative demonstration of the developing law of SF6 block.There is an evident discrepancy between the three numerical simulations for the maximum position of the right edge of block at the late stage,because the right interface grows complicated and the dissipation is different for different SGS models.The SGS turbulent dissipation,molecular viscosity dissipation and SGS turbulent kinetic energy have been studied and analyzed.They have a similar distribution to the large eddy structures.The SGS turbulent dissipation is much greater than the molecular viscosity dissipation;the SGS turbulent dissipation of Vreman model is smaller than the Smagorinsky model.In general,the simulated results of Vreman SGS model are better compared with the dynamic viscosity and Smagorinsky SGS model.The vorticity and circulation deposition on the block interface have also been investigated.

关键词： large-eddy simulation Navier-Stokes equations subgrid-scale Richtmyer-Meshkov instability turbulent dissipation turbulent kinetic energy circulation deposition

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激波管中Richtmyer-Meshkov不稳定性的实验研究

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激波管中Richtmyer-Meshkov不稳定性的实验研究

Richtmyer-Meshkov失稳的数值模拟

中国科协第235次青年科学家论坛——极端复杂测试环境下...

作者：罗喜胜司廷杨基明中国科学技术大学近代力学系激波实验室

当激波作用于不同密度的物质界面时,界面将获得有限的加速度,界面上的扰动会逐渐演化发展,最终出现不断扩展的湍流混合层,这就是Richtmyer-Meshkov(RM)不稳定性问题。RM不稳定性问题是一种十分复杂的多尺度强非线性物理问题,是高能量密... 详细信息

当激波作用于不同密度的物质界面时,界面将获得有限的加速度,界面上的扰动会逐渐演化发展,最终出现不断扩展的湍流混合层,这就是Richtmyer-Meshkov(RM)不稳定性问题。RM不稳定性问题是一种十分复杂的多尺度强非线性物理问题,是高能量密度物理研究的主要内容之一,在天体物理、惯性聚变能源、水中炸药爆炸、航天火箭发动机、国防尖端武器等领域有着重要而广泛的研究背景。

关键词：激波管 Richtmyer-Meshkov 不稳定性

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计算物理 2001年第5期18卷 390-396页

作者：程军波傅德薰马延文 LNM 中国科学院力学所北京100080 LHD 中国科学院力学所北京100080

利用五阶迎风紧致差分格式加群速度控制方法对激波与轻气体柱形界面的干扰问题进行直接数值模拟 ,并研究了涡量的产生及其发展和界面的变形 ,分析了柱形界面的失稳过程 ,得知在线性发展阶段 ,重气体以恒定的速度进入到轻气体中 ,并形成... 详细信息

利用五阶迎风紧致差分格式加群速度控制方法对激波与轻气体柱形界面的干扰问题进行直接数值模拟 ,并研究了涡量的产生及其发展和界面的变形 ,分析了柱形界面的失稳过程 ,得知在线性发展阶段 ,重气体以恒定的速度进入到轻气体中 ,并形成尖钉结构 ;在非线性发展阶段 ,在尖钉头部的两侧形成一对旋转方向相反的涡结构 .同时证实了激波与界面的相互干扰有助于增加混合 .并将所得的数值解与实验结果进行了比较 .

关键词：五阶迎风紧致差分格式群速度控制格式 Richtmyer-Meshkov 失稳轻气体柱形界面斜压效应数值模拟激波干扰

Air/SF6界面Richtmyer-Meshkov不稳定性实验研究

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Air/SF6界面Richtmyer-Meshkov不稳定性实验研究

Numerical study of three-dimensional developments of premixed flame induced by multiple shock waves

第十二届全国实验力学学术会议

作者：刘金宏邹立勇黄文斌谭多望流体物理研究所冲击波物理与爆轰物理国防科技重点实验室

两种不同密度流体交界面的扰动发展主要受Rayleigh-Taylor(R-T)不稳定性、Richtmyer-Meshkov(R-M)不稳定性和Kelvin-Helmholtz(K-H)不稳定性的影响:在重力或惯性力的质量力作用下不同流体界面的不稳定为R-T不稳定性;当激波作用流体界面... 详细信息

两种不同密度流体交界面的扰动发展主要受Rayleigh-Taylor(R-T)不稳定性、Richtmyer-Meshkov(R-M)不稳定性和Kelvin-Helmholtz(K-H)不稳定性的影响:在重力或惯性力的质量力作用下不同流体界面的不稳定为R-T不稳定性;当激波作用流体界面时,也会引起界面的失稳,这种不稳定称为R-M不稳定性;两种流体界面存在速度差,造成界面的扰动发展,这种失稳称为K-H不稳定性。这些界面不稳定性现象无论在自然界(天体物理或地球),还是在惯性约束聚变(ICF),高速碰撞和加速等高技术领域中都是客观存在的,甚至在水力机械以及各种发动机也都是非常重要。界面不稳定性非线性阶段比较清楚,但非线性阶段和后期的湍流混合还有很多需要认识,相关研究具有十分重要的实际和理论价值。

关键词： Richtmyer-Meshkov 不稳定性气气界面高速摄影

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Acta Mechanica Sinica 2018年第6期34卷 1035-1047页

作者： Xiao Chen Gang Dong Baoming Li Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China

The three-dimensional interactions of a perturbed premixed flame interface with a planar incident shock wave and its reflected shock waves are numerically simulated by solving the compressible,reactive Navier-Stokes equations with the high-resolution scheme and a single-step chemical reaction.The effects of the initial incident shock wave strength (Mach number) and the initial perturbation pattern of interface on the interactions are investigated.The distinct properties of perturbation growth on the flame interface during the interactions are presented.Our results show that perturbation growth is mainly attributed to the flame stretching and propagation.The flame stretching is associated with the larger-scale vortical flow due to richtmyermeshkov instability while the flame propagation is due to the chemical reaction.The mixing properties of unburned/burned gases on both sides of the flame are quantitatively analyzed by using integral and statistical diagnostics.The results show that the large-scale flow due to the vortical motion always plays a dominating role during the reactive interaction process;however,the effect of chemistry becomes more important at the later stage of the interactions,especially for higher Mach number cases.The scalar dissipation due to the molecular diffusion is always small in the present study and can be negligible.

关键词： Flame interface instability Richtmyer-Meshkov instability Large-scale flow Chemical reaction Scalar dissipation

Numerical study on the turbulent mixing of planar shock-accelerated triangular heavy gases interface

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Acta Mechanica Sinica 2018年第5期34卷 855-870页

作者： Wei-Gang Zeng Jian-Hua Pan Yu-Xin Ren Yu-Tao Sun Department of Engineering Mechanics School of AerospaceTsinghua UniversityBeijing 100084China Institute of Applied Physics and Computational Mathematics Beijing 100094China

The interaction of a planar shock wave with a triangle-shaped sulfur hexafluoride (SF6) cylinder surrounded by air is numerically studied using a high resolution finite volume method with minimum dispersion and controllable dissipation reconstruction.The vortex dynamics of the Richtmyer-Meshkov instability and the turbulent mixing induced by the KelvinHelmholtz instability are discussed.A modified reconstruction model is proposed to predict the circulation for the shock triangular gas-cylinder interaction flow.Several typical stages leading the shock-driven inhomogeneity flow to turbulent mixing transition are demonstrated.Both the decoupled length scales and the broadened inertial range of the turbulent kinetic energy spectrum in late time manifest the turbulent mixing transition for the present case.The analysis of variable-density energy transfer indicates that the flow structures with high wavenumbers inside the Kelvin-Helmholtz vortices can gain energy from the mean flow in total.Consequently,small scale flow structures are generated therein by means of nonlinear interactions.Furthermore,the occasional 'pairing' between a vortex and its neighboring vortex will trigger the merging process of vortices and,finally,create a large turbulent mixing zone.

关键词： Richtmyer-Meshkov instability Kelvin-Helmholtz instability Length scale Turbulent mixing