The effect of a short-wavelength mode on the evolution of a long-wavelength perturbation driven by a strong blast wave

Shock-accelerated material interfaces are potentially unstable to both the Richtmyer-Meshkov and Rayleigh-Taylor (RT) instabilities. Shear that develops along with these instabilities in turn drives the Kelvin-Helmholtz instability. When driven by strong shocks, the evolution and interaction of these instabilities is further complicated by compressibility effects. This paper details a computational study of the formation of jets at strongly driven hydrodynamically unstable interfaces, and the interaction of these jets with one another and with developing spikes and bubbles. This provides a nonlinear spike-spike and spike-bubble interaction mechanism that can have a significant impact on the large-scale characteristics of the mixing layer. These interactions result in sensitivity to the initial perturbation spectrum, including the relative phases of the various modes, that persists long into the nonlinear phase of instability evolution. Implications for instability growth rates, the bubble merger process, and the degree of mix in the layer are described. Results from relevant deceleration RT experiments, performed on OMEGA [J. M. Soures , Phys. Plasmas 5, 2108 (1996)], are shown to demonstrate some of these effects. (C) 2004 American Institute of Physics.