平面激波诱导斜界面失稳的大涡模拟

Large eddy simulation of inclined interface instability induced by planar shock wave

近年来国内外学者从多个角度深入地研究了经典平面激波与相界面之间的相互作用规律,但针对平面激波与气-液斜界面的研究仍不够系统和全面,探究平面激波驱动气-液斜界面失稳过程的演化规律在超声速燃烧和惯性约束聚变等工程应用中具有重要的实际意义。本工作结合VOF模型和大涡数值模拟方法,研究了平面激波诱导气-液两相斜界面变形和湍流混合的现象,分析了入射激波马赫数、入射激波初始倾角和斜界面倾角等因素对界面失稳的影响规律。结果表明,入射激波马赫数大小是界面失稳现象发展的主要影响因素,增大激波马赫数可明显地增强界面变形和湍流混合现象的发展程度。入射激波初始倾角和斜界面倾角对界面失稳发展也有一定影响。随着入射激波和斜界面倾角增大,相同时刻时的湍流混合区宽度相应增加。

Interfacial instability and its induced interfacial deformation and turbulent instability are widely used.In medium characteristic scale supersonic combustion,the interfacial instability enhances the mixing of fuel and combustion aids.In small characteristic scale inertial confinement fusion,the turbulent mixing induced by interfacial instability dilutes and cools the fuel twice,thus reducing the reaction rate and even causing ignition failure.In recent years,scholars at home and abroad have deeply studied the interaction between the classical planar shock wave and the phase interface from many angles,but the research on the interaction between the shock wave and the gas-liquid oblique interface is still not systematic and comprehensive.It is of great significance to explore the evolution of shock driving gas-liquid interface instability in practical engineering applications such as supersonic combustion and inertial confinement fusion.In the process of numerical simulation,VOF model is used,combined with large eddy simulation method and appropriate boundary conditions to study the evolution process of shock induced gas-liquid two-phase oblique interface deformation and turbulent mixing in two-dimensional plane.The influence of Mach number of incident shock,initial inclination angle of shock and inclined interface inclination angle on interface instability is analyzed.The results show that the Mach number of incident shock is the most important factor in the development of interface instability.Under the same conditions,compared with the other two factors,increasing the shock Mach number can significantly increase the interface deformation and the development of turbulent mixing.At the same time,the number of serrated structures on the interface increases,the forming speed is obviously accelerated,and the width of turbulent mixing zone increases obviously.In addition,with the increase of the initial angle of shock wave and inclined interface angle,the number and forming speed of serrated structure on the interface increase at the same time,and the width of turbulent mixing zone also increases.