Studies on the Nonlinear Evolution of the Richtmyer-Meshkov Instability

A statistical model predicting the evolution of turbulent mixing zone fronts was developed recently by Alon et al. It suggests that the three physical elements that govern the Rayleigh-Taylor and Richtmyer-Meshkov mixing zone evolution are the single-bubble evolution, the single-spike evolution, and the interaction between neighboring bubbles. In this paper we present an experimental investigation of these three elements in the Richtmyer-Meshkov case. The experiments were performed in a double-diaphragm shock tube. The interface evolution was studied both before and after the arrival of a secondary reflected shock. Experimental results for the single-bubble and two-bubble cases show distinct bubble and spike evolution. The results of the bubble competition, which determines the front evolution, were found to be in good agreement with both full numerical simulations and a simple potential flow model. These results strengthen the assumptions on which the statistical model is based.