Physics of the single-shocked and reshocked Richtmyer–Meshkov instability

Abstract

This paper presents a numerical study of a single-shocked turbulent mixing layer using high-order accurate implicit large-eddy simulations (ILES) for low- and high-amplitude (linear and non-linear) perturbations and for a reshocked turbulent layer. It investigates the differences in flow physics between these three cases, examining a recent proposition that single-shocked high-amplitude initial perturbations can be employed to model a reshocked turbulent layer. At early times, the shocked high-amplitude perturbation has high levels of mixing; however, at later times, it grows in an almost identical manner to the low-amplitude case. Despite exploration of several choices of scaling to map the reshocked results to the single-shocked study, a satisfactory agreement could not be reached and mixing parameters remain disparate. The conclusion is that a single-shock interaction with a high-amplitude perturbation is not a good representation of reshock of a turbulent mixing layer.

Keywords:

• Richtmyer-Meshkov instability
• turbulent
• mixing
• implicit large eddy simulation

Acknowledgements

The authors would like to acknowledge the EPSRC (Engineering and Physical Sciences Research Council) in relation to computational resources (project EP/G069735/1). The computations were run on Cranfield’s Astral supercomputer and the HECToR (High-End Computing Terascale Resources) National Facility.