反射激波作用下重气柱界面演化的PIV研究

在水平激波管中采用PIV方法研究了反射激波作用下SF6重气柱界面的发展演化。采用射流方法形成SF6无膜气柱界面,并以乙二醇作为示踪粒子。利用连续激光片光源结合高速摄影相机对流场进行显示,得到了反射激波作用下SF6气柱界面的发展过程。结果表明,入射激波的冲击会在界面上产生反向旋转的涡环结构,而反射激波的作用会在界面上产生与初始涡环旋转方向相反的次级涡环结构。此外,对反射激波作用后的流场图像进行PIV后处理,获得了流场连续的速度场和涡量场。获得的环量与已有的理论模型进行比较,取得了较好的一致性,也验证了本文实验方法的可行性。

Experimental study on the evolution of heavy gas cylinder under reshock condition by PIV method

Evolution of a membrane-less heavy （SF6 ）gas cylinder under reshock condition is experimentally investigated in a horizontal shock tube with particle image velocimetry （PIV ） method.As a fundamental interface configuration,gas cylinder evolution impinged by a single shock wave is extensively investigated while the related research under reshock condition is seldom performed.Illuminated by a continuous laser sheet,the interface morphology after the incident shock and reshock impact is characterized by glycol droplets and captured by a high-speed camera.The generation and development of counter-rotating vortex pair after incident shock impact is observed and secondary vortex rings,which have opposite rotating directions with the original vortex rings,are generated after the reshock passage because of the opposite pressure gra-dient induced by reshock compared with the incident shock.Because the velocity of the flow field after reshock is very small,the PIV measurement based on the Matpiv procedure is employed to capture the flow field after reshock.The continuous velocity and vorticity fields are obtained with the help of the continuous light source and high speed camera.Compared with the PIV algorithm based on the double-exposure technique,continuous velocity field can be obtained in a single test run based on the high-speed technique in this experiment.The circulation derived from PIV measurements is compared with the existed analytical model and a good agreement is achieved, which validates the feasibility of the experimental method.