Numerical Study of Shock Wave Impacting on the Double-Mode Interface in Nonuniform Flows

The double-mode Richtmyer-Meshkov (RM) instability, when the incident shock (Ma=1.27) impacting on several groups of initial double-mode cosine interface formed by different amplitudes in initially nonuniform flows whose density is Gaussian distribution, was numerically investigated using the large-eddy simulation code MVFT (multi-viscous-flow and turbulence).The numerical results show that the coupling effects between different amplitudes in the nonuniform flows are weak and the evolution of the interface with a large initial amplitude in the low density nonuniform area grows fastest, while that with a small initial amplitude in the high density nonuniform area grows slowly.Further analyses reveal that within a certain initial amplitude range, the amplitude growth rate and energy in the low density zone of nonuniform flows is larger than those in the high density zone, thus the influence of the initial amplitude on the low density zone is more obvious, which eventually leads to a faster evolution process of the RM instability.Moreover, the changing phenomena of uniform flows are opposite to nonuniform flows.Thus, it can be concluded that the evolution mechanisms of the RM instability between the nonuniform and uniform flows are distinctive.