On the P-23 Extreme Fluids Team at Los Alamos National Laboratory, we apply high-resolution diagnostics to study fluid dynamics problems in extreme environments, such as shock-driven mixing and variable-density decaying turbulence. The team is composed of Los Alamos staff, postdocs, and students.
The team has three experimental facilities to study multiphase flows, mixing, and turbulence:
The Vertical Shock Tube (VST) is designed to study shock-driven mixing of two fluids that are struck by a shock wave. We study the perturbations at the interface between the fluids, and how they grow due to the passage of the shock and mix the two fluids. Simultanous velocity and density field diagnostics (and soon to be implemented tomographic PIV) are used to study fluid properties and turbulence quantities.
The Turbulent Mixing Tunnel (TMT) studies the mixing of two fluids in a subsonic environment in order to quantify how momentum and buoyancy forces enhance or suppress mixing at various times in the flow. This facility also measures turbulence quantities for the development of better models for variable-density mixing.
The Horizontal Shock Tube (HST) is designed to study the response of particles and droplets in a gas to the passage of a shock wave, characterized by very strong accelerations. In these circumstances, the flow is unsteady, and our normal drag coefficients will not properly predict the motion of the particles. This facility is using an 8-pulse laser system with a high-speed camera to measure particle velocities and accelerations over very short time scales.
In our last experiments of the Richtmyer-Meshkov instability at the Horizontal Shock Tube, we apply high-resolution velocity and density field diagnostics (PIV and PLIF) to study the development of shock-driven hydrodynamic instabilities. The movie, below, is experimenta data that shows the passage of a Mach 1.5 shock (cartoon, orange line) passing through an SF6 gas curtain and the resulting growth of the instabilities in the gas curtain. Each image is about 50 µs apart, and the movie runs for 1250 µs after shock passage through the initial conditions. Experimental data were taken by Greg Orlicz and Sridhar Balasubramanian and have recently been published in Physics of Fluids (see the publications link to the left).