Stabilization of short-wavelength disturbances in the Rayleigh--Taylor instability of plastic solids by a surface layer of high yield strength

Abstract

The mechanical effects of a thin surface layer in reducing the growth of the Rayleigh-Taylor instability of a plastic solid plate is investigated by representing the surface layer as an elastic plate of high yield strength and high bonding strength to the plastic. This plate may be either the surface layer itself or a composite material formed by interactions of the surface layer with the solid surface layers. In this approximation it is found under wide ranges of conditions that short-wavelength disturbances are stabilized in linear approximation. In this limit the ''gravitational'' energy increment of the displaced plastic solid is overcome by the elastic shear energy of the stretched plate. Long-wavelength disturbances are very weakly affected by this mechanism. For a plastic plate of approximately 1-cm thickness subjected to a pressure difference of approximately 100 kbar we expect wavelengths shorter than lambda/sub c/ approximately 10/sup -1/ cm to be effectively stabilized by this mechanism.