Experimental Study of a Shock-Accelerated Gas Flow Non-Uniformly Seeded With Droplets*

We present an experimental study of a gas flow which is partially seeded with a modest volume fraction of submicron-sized droplets and subjected to shock acceleration. Under these conditions an instability similar to Richtmyer-Meshkov develops. In our experiments, a planar shock front traveling horizontally through air meets a vertical column of gas (either air or SF6) that is seeded with particles. After shock interaction, the column is compressed and deformed, and a pair of counter-rotating vortices forms. The evolution of the flow is tracked with a multiple-CCD digital camera, allowing to capture up to four laser sheet-illuminated images per single experiment. We discuss the flow features in shocked and reshocked flows at a range of Mach numbers from 1.2 to 2.