A Study of Chaos and Mixing in Rayleigh-Taylor and Richtmyer-Meshkov Unstable Interfaces.
NEW YORK UNIV NY COURANT INST OF MATHEMATICAL SCIENCES
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Instabilities of fluid interfaces give rise to entrainment and to a chaotic mixing layer. This report has three purposes. The authors discuss the general features of such chaotic mixing layers, formulate a scientific program for their study and report on their recent progress in carrying out portions of this program. The Rayleigh-Taylor instability is driven by an inertial or gravitational force accelerating an interface between fluids of differing densities. Thus with the heavy fluid above the lighter fluid a flat horizontal interface in a gravitational field is in a position of unstable equilibrium. Small disturbances grow, producing bubbles of light fluid rising in the heavy fluid and spikes - or droplets of heavy fluid falling in the light fluid. The Richtmyer-Meshkov instability is produced by a shock wave hiring an interface a contact discontinuity or material boundary separating fluids of differing densities. Assuming a planar shock wave normally incident on an interface slightly perturbed from planar, the initial disturbances in the interface are again unstable, and grow with time.
- Fluid Mechanics