Abstract
In this work, we investigate the evolution of a Richtmyer-Meshkov
(RM)-like instability occurring on the internal surface of particle
rings impinged by divergent blast waves. Despite of the signature
spike-bubble instability structure analogous to the hydrodynamic RM
instability, the growth of the perturbation amplitude in granular media
undergoes an exponential phase followed by a linear phase, markedly
differing from the hydrodynamic RM instability, indicating a
fundamentally different mechanism. The granular RM-like instability
arises from the incipient transverse granular flows induced by the
hydrodynamic effects upon the shock interaction. Whereas a substantial
perturbation growth is initiated by the ensuing rarefaction dilation
when the hydrodynamic effects are minimum. It is the interplay between
the localized transverse and radial granular flows that sustains the
persistent perturbation growth and drives the morphological changes of
instability pattern alongside.