Interaction of a heavy-particle curtain with shock and reshock

A gravity-driven particle curtain is accelerated by a planar shock, which is then reflected from a wall perpendicular to the shock direction. We visualize the curtain evolution at several initial curtain thicknesses (2, 4, 6 mm) in the streamwise direction and for Mach numbers ranging from 1.1 to 2.0. Additionally we record pressure traces from multiple transduces both upstream and downstream of the initial location of the curtain. Non-uniformities in the initial particle concentration in the curtain result in differences in the local average density, in turn triggering shock-driven multiphase instability (SDMI), most clearly observable on the trailing (upstream) edge of the curtain. We also observe the effects of the gradual particle seeding density decrease along the vertical curtain extent due to falling particle acceleration. Despite the modest (about 5%) particle fraction in the curtain, particle inertia effects appear quite prominent.