A Mach number study of the Richtmyer - Meshkov instability in a varicose, heavy-gas curtain

Abstract

A varicose-perturbed, thin, heavy-gas curtain is impulsively accelerated by a planar shock wave of varying strength and investigated experimentally using concentration field visualization. Experiments were performed with Mach 1.2 and 1.5 incident shock waves, acquiring images of the initial conditions, and 18 different times after shock interaction in each case. Repeatability of the initial conditions allows for visualization of flow feature development over time for both Mach numbers despite capturing only one dynamic, postshock image per run of the experiment. Good agreement between integral width experimental data and a mixing width model is demonstrated for early to intermediate times in the flow. Integral width growth rates for Mach 1.2 and 1.5 are shown to collapse using a scaling based upon the convection velocity of the curtain. The diffusion driven instantaneous mixing rate, is also estimated and compared between experiments. Results from this gradient based metric show differences in mixing trends between Mach numbers that do not scale in the same way as integral width, suggesting that integral width alone is insufficient for completely describing the flow. An experiment with a Mach 2.0 incident shock was carried out for the first time in the experimental facility. The resulting image provides further evidence for the mixing trends observed in this paper as Mach number is increased. © 2009 American Institute of Physics.