We present a two-dimensional computational study of a shock interaction with a particle-seeded curtain where particles initially comprise 4% by volume, and the rest is air. If the initial depth of the curtain in the streamwise direction is variable, numerical results predict vortex formation in both the gas phase and the dispersed phase after the shock-curtain interaction. The phenomenon is distinct from baroclinic (Richtmyer-Meshkov) instability observed on gaseous density interfaces and is caused by the changes in the particle phase number density distribution and related interphase velocity changes.

Falling particle curtains are important in many engineering applications, including receivers for concentrating solar power facilities. During the formation of such a curtain, we observe a multiphase analog of Rayleigh-Taylor instability (RTI). It was originally described in 2011 for a situation when air sparsely seeded with glycol droplets was placed above a volume of unseeded air, producing an unstably stratified average density distribution that was characterized by an effective Atwood number 0.03. In that case, the evolution of the instability was indistinguishable from single-phase RTI with the same Atwood number, as the presence of the droplets largely acted as an additional contribution to the mean density of the gaseous medium. Here, we present experiments where the volume (and mass) fraction of the seeding particles in gas is considerably higher, and the gravity-driven flow is dominated by the particle movement. In this case, the evolution of the observed instability appears significantly different.