Numerical investigation of reactive and non-reactive richtmyer-meshkov instabilities

Abstract

The Richtmyer-Meshkov instability (RMI) arises from the interaction of a shock wave with a density gradient in a fluid. The density gradient can be caused by temperature and/or species concentration. The RMI leads to strong mixing and in the case of reactive flows an existing flame will be accelerated. Such acceleration processes can lead to a transition to detonation. This work presents first results in the simulation of these instabilities driven by a shock induced acceleration. It examines the case of single-mode interface perturbations and compares its growth and behaviour for reactive and non-reactive flows. The chemistry is described by a multiple-species one-step Arrhenius based kinetics model. The skew-symmetric finite difference formulation of the Navier-Stokes equations is used to simulate the flow. Ideal gases of stoichiometric premixed methane-air, i.e. CH4+2O2+7.52N2, are considered. The starting point is the validation of the physical model. Subsequently the role of the RMI in the transition to detonation is analysed by testing the influence of the shock Mach number on the onset of detonations.