High-Speed Simultaneous Velocity and Concentration measurements of the Richtmyer-Meshkov Instability Upon Re-Shock*

The Richtmyer-Meshkov instability of a twice-shocked gas interface is investigated in the vertical shock tube of the Wisconsin Shock Tube Laboratory at the University of Wisconsin– Madison. The initial condition is a shear layer, containing broadband perturbations, formed at the interface between a helium-acetone mixture and argon.

The interface is accelerated with a shock of nominal strength M=1.76 with an initial Atwood number A=0.5.

Concurrent, high-speed planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) are performed using a pulse-burst laser operating at 20,000 Hz. The 266 nm and 532 nm laser outputs are co-propagated into the shock tube, forming a dual wavelength light sheet. Acetone is added to the helium to act as a fluorophore; 200 nm titanium dioxide particles are added to both the helium and the argon to perform PIV. Images are collected with two high-speed CMOS cameras.

Presented preliminary results will include integral measures, such as thickness and mixedness; spectral quantities, including scalar and kinetic energy spectra; combined moments and structure functions.