Instabilities in a shock interaction with a perturbed curtain of particles

Abstract

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.

Formation of a falling particle curtain

“…We also seek to understand growth rates by conducting numerical analysis using an approach similar to the Eulerian-Lagrangian study of the particle-laden RMI [6].…”

“…is distributed non-uniformly, leading to the existence of gradients of average density. Recently, it was demonstrated [4]- [6] that analogues of RMI and RTI exist in such flows subjected either to gravity or to impulsive (shock) acceleration. The analogue of RMI [4] is known as shock-driven multiphase instability (SDMI) [6], [7].…”

“…Recently, it was demonstrated [4]- [6] that analogues of RMI and RTI exist in such flows subjected either to gravity or to impulsive (shock) acceleration. The analogue of RMI [4] is known as shock-driven multiphase instability (SDMI) [6], [7]. As in the case of classical RMI, a dimensionless number similar to the Atwood number (eqn (1)) plays a key role in SDMI: the multiphase Atwood number [8] Here, the subscript s characterizes the volume-averaged properties of the seeded flow (embedding phase together with embedded phase), and the subscript u the properties of the unseeded embedding phase.…”