PIV Analysis of the Richtmyer-Meshkov Instability for a He/SF$_{6}$ Interface

Experiments are presented for the Richtmyer-Meshkov instability of a nearly single mode interface of helium over sulfur hexafluoride. The initial condition is an interface created by oscillating a pair of rectangular pistons to form a nearly 2D sinusoidal standing wave in a vertical shock tube. The incident shock wave ($M$ = 1.2) deposits a large amount of vorticity on this high Atwood number ($A$ = ($\rho _{2}$--$\rho _{1})$/($\rho _{2}+\rho _{1})$ = 0.95) interface resulting in amplitude growth and asymmetrical spike/bubble development. Particle imaging velocimetry (PIV) is accomplished by seeding the top gas with Al$_{2}$O$_{3}$ particles and acquiring a pair of planar images that are analyzed to obtain the velocity field. Experimentally determined amplitude growth rate, circulation, and energy spectra are compared with models and numerical simulations.