Spatiotemporal evolution of hydrometeors and flow interactions during aerobreakup

Hydrometeors consisting of liquid water droplets or solid particles of ice can disrupt the boundary layer near hypersonic vehicles, and ultimately impinge on the surface causing surface roughness and further altering the flowfield. To advance the knowledge of hydrometeors and their impact on hypersonic flight, it is critical, therefore, to develop practical, high-fidelity and spatio-temporally resolved three-dimensional measurements of their behavior under relevant conditions. The proposed research effort will (i) demonstrate and characterize three-dimensional imaging of hydrometeor aerobreakup in test facilities of interest to the ONR, especially for the most complex flowfields, (ii) optimize imaging schemes to cover a wide range of spatiotemporal scales and reduce ambiguities along the line of sight, (iii) simultaneously image the gas-phase using techniques such as laser-induced fluorescence, backward oriented schlieren, Rayleigh scattering, and/or molecular tagging to capture three-dimensional state variables such as density, temperature, velocity, and species, and (iv) explore a portable diagnostics suite based on flexible, high-speed illumination sources that can be utilized with various detection or imaging modules and are carefully designed for test facilities of interest. This will lead to data on quantitative imaging of hydrometeor aerobreakup and a prototype commercial instrument for use in hypersonic test facilities.