SUMMARY

This PhD work is on investigating coupled buoyancy-driven (Rayleigh-Taylor) and shear-driven (Kelvin-Helmholtz) instabilities using statistically stationary experiments conducted in gas tunnels. Employing diagnostics like particle image velocimetry (PIV) and planar laser induced fluorescence (PLIF), we make simultaneous velocity-density measurements in order to study how dynamics and mixing are linked in variable density flows. In addition to extracting quantities of statistical importance from our measurements (like density-velocity correlations), we also look at how different forces (for example, buoyancy and shear) fundamentally drive variable density mixing process (using nondimensional parameters like Richardson number), and how such mixing processes reach an asymptotic state (using measures of molecular mixing). These experiments are of immense significance for atmospheric and oceanic sciences, and for developing and validating variable density turbulence models. One can also join the talk virtually via https://gatech.zoom.us/j/96700983052