Rayleigh-Taylor Instability for Adiabatically Stratified Fluids

A linear analysis of the effects of compressibility on the stability of two superposed isentropic fluids is presented. The results of the analysis, which differ from those available in the literature for other unperturbed stratifications, are illustrated with several numerical examples. It is found that, in the present conditions, compressibility has a stabilizing effect at small wavelengths and a destabilizing effect at long wavelengths. The magnitude of these effects is, however, small in most circumstances. A physical basis for the interpretation of the results is also described in qualitative terms. This discussion sheds some light on the nature of the differences between the present results and those relative to the case of isothermal stratification.