Turbulent Mixing in Late-Time Richtmyer-Meshkov Instability Experiments

The Richtmyer-Meshkov instability is experimentally investigated in a vertical shock tube using a broadband initial condition imposed on an interface between a helium-acetone mixture and argon ($A $= 0.7). The initial condition is created, first by setting up a gravitationally stable stagnation plane between the gases, and then injecting the same two gases horizontally at the interface to create a shear layer. The perturbations along the shear layer create a statistically-repeatable broadband initial condition. The interface is accelerated by a $M$ = 1.6 or $M$ = 2.2 planar shock wave and develops into a fully-developed turbulent state. Mixing measurements are made using planar laser-induced fluorescence (PLIF). The spectra, length scales, and isotropy after the turbulent mixing transition are presented.