The Richtmyer-Meshkov instability of a "V"shaped air/SF6 interface accelerated by a planar incident shock and its reshock was experimentally investigated in a shock tube.The soap film tech-nique was adopted to form a well-controllable initial interface,and the flow field was captured by a high-speed schlieren system.Through changing the vertex angle of the interface,the initial perturba-tion amplitude was varied,and the effect of the initial perturbation amplitude on the wave pattern and the flow morphology was highlighted.The results show that,after the impact of the incident shock, the interface morphology is different for different vertex angles,further causing the diversity of the interface morphology after the reshock impact.For the interfaces with small vertex angles,the compli-cated wave patterns will emerge inside and outside the interface after the reshock,which exert an influence on the interface morphology and phase inversion phenomenon.The flow enters the turbulent mixing quickly after the reshock,and the development of interface for small vertex angles tends towards isotropy.Moreover,the mixing width after the reshock was measured from experiments and compared with the theoretical predictions.The model was found to be invalid mainly because the initial conditions of the experiments violate the requirement of the model.%在激波管中实验研究了二维V形空气/SF6界面在入射激波和反射激波作用下的Richtmyer-Meshkov不稳定性发展规律.实验中采用细针约束肥皂膜的方法形成了精确可控的V形初始界面,利用高速纹影技术获得了受冲击的V形界面演化图像.通过改变初始V形界面顶角表征初始扰动振幅,获得了不同初始振幅条件下的波系和界面演化.结果表明,不同顶角下,入射激波冲击过后,界面形态表现出明显的差异,进一步导致反射激波冲击后界面形态的多样性.当顶角较小时,反射激波在界面内外引起复杂的波系结构,从而对界面形态及反相现象产生较大的影响.反射激波的二次作用使流场快速进入湍流混合状态,并且顶角较小时流场趋于各向同性发展.对反射激波作用后的界面混合宽度进行了测量,并与理论模型预测结果进行对比,发现理论模型不能很好地预测混合宽度的增长,主要是因为反射激波作用之后流场并没有完全达到湍流混合状态,不符合理论模型的适用条件.
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