Experimental investigation of the inclined interface Richtmyer–Meshkov instability before and after reshock

Abstract

An experimental study on the Richtmyer–Meshkov instability (RMI) is presented, which used a new experimental facility at Texas A&M University built for conducting shock-accelerated, inhomogeneous, inclined fluid interface experiments. The RMI develops from the misalignment of the pressure and density gradients for which the inclined shock tube facility is uniquely well suited since a fluid interface can be created at a prescribed angle to the incident shock. Measurements of the evolving RMI are taken using planar laser Mie scattering images for both the pre- and post-reshock regimes, which capture the qualitative evolution of the interface. Statistical measurements demonstrate that the inclined interface initial conditions have a high degree of run-to-run repeatability. The interface mixing width is scaled using the method developed in author’s previous work and shows that the non-dimensional mixing width grows linearly in the pre-reshock regime and then levels off at the onset of reshock, after which it grows linearly again. Mie scattering images at late times exhibit the evolution of a secondary shear instability on the primary vortex feature, which has never been resolved in simulations of the inclined interface RMI. A 2D velocity field is obtained for this feature using particle image velocimetry and processed to indicate the strength of the vorticity present. Images of the interface after reshock reveal the inversion of the bubble and spike features and the decay of prominent features toward a turbulent state.