525 / 2019-03-19 21:19:35

Interaction of shock wave with double heavy-gas cylinders

RMI,Shock-cylinder interaction,Cylinder coupling

全体主题 > Interface Instabilities at Extremes

When a perturbed interface separating two different fluids is impulsively accelerated, the initial perturbation on the interface gradually grows due to the induction of the baroclinic vorticity deposited on the interface and eventually the turbulent mixing emerges, which is known as Richtmyer-Meshkov instability (RMI). In view of the considerable academic value and extensive engineering applications of RMI in the fields of the supersonic combustion ramjet, supernovas explosion as well as inertial confnement fusion and so on, many researchers have conducted extensive and in-depth research on RMI and achieved fruitful results in the past few decades. Simultaneously, the shock-cylinder interaction (SCI) has been considered as one of the most fundamental configurations for studying the evolution of RMI. In this work, the evolution of double heavy-gas cylinders impacted by a converging/planar shock wave is experimentally investigated and some typical experimental phenomena which differ from the previous related studies are observed.
Experiments are respectively carried out in a horizontal shock tube and a horizontal converging shock tube without the reflected shock, and the interaction of the converging/planar shock with double heavy-gas cylinders can be captured by a high-speed schlieren system. And the numerical method 2-Dimensional Vectorized Adaptive Solver (VAS2D) is applied to simulate the shock-cylinder interactions. Based on the experimental and numerical schlieren images, some unique phenomena such as the mushroom structures and twisted jets can be observed at the downstream interface of the evolving gas cylinders, which are opposite to the previous related studies. In the previous studies, the movements of the inner vortices near the symmetric axis of the double cylinders relative to the outer vortices are toward the upstream and spanwise directions. Nevertheless, the relative movements of the inner vortices in this work are toward the downstream as well as symmetric axis and lead to the formation of the mushroom structures, which may originate from the gas diffusion being effectively suppressed by the experimental methods in this work compared to the previous studies. And results show the evolution law of the double cylinders accelerated by a converging shock is quite different from the one accelerated by a planar shock, which may be ascribed to the coupling of multiple effects (i.e. the BP effect, the nonlinear effect as well as the cylinder coupling and so on) under converging case.