Experimental Study of Richtmyer-Meshkov Instability in Nonuniform Flow by Shock Tube
激波管实验研究非均匀流场R-M不稳定性

Richtmyer-Meshkov instability in SF6 nonuniform flow was experimentally studied by producing a weak incident shock wave with Mach number 1.27 in a shock tube.Initial sinusoidal interface between Air/SF6 was formed by a polymeric membrane with thickness of 0.5μm and the interface evolution was measured by using shadowgraph method.Experimental result show that the instability is characterized by "spike"of heavy fluid falling into lighter fluid and the bubbles of lighter fluid rising into heavy fluid.At the edge of spike,rolling mushroom occurs due to Kelvin-Helmholtz instability produced by the defference of interface tangential velicities.Evolution of flow disturbance grows faster in the low density zone due to the initial density nonuniformity in flow field.Experimental results of disturbance amplitude growth are in good agreement with PPM simulation results.