Shock tube experiments and numerical simulation of the single-mode, three-dimensional Richtmyer–Meshkov instability

Abstract

A vertical shock tube is used to perform experiments in which an interface is formed using opposed flows of air and SF6. A three-dimensional single-mode perturbation is created by the periodic vertical motion of the gases within the shock tube. Richtmyer–Meshkov instability is produced by an impulsive acceleration by a weak shock wave (Ms=1.2). Planar laser induced fluorescence produces still images, and planar Mie scattering produces movies of the experiment. A three-dimensional numerical simulation of this experiment utilizing the Eulerian adaptive mesh refinement code, RAPTOR, was also conducted. Good agreement is obtained between experiments and the simulations. However, existing late time models, which have a 1/t dependence, disagree with measurements of the late time instability development. In contrast, both the experiments and simulation suggest a t−0.54 late time dependence for the overall growth rate. Comparisons with individual bubble and spike velocities show the bubbles appear to decay approximately at 1/t and the spikes to decay at a much slower rate of t−0.38.