The Rayleigh–Taylor instability of the externally cooled liquid lying over a thin vapor film coating the wall of a horizontal plane heater

The linear instability of a vapor film formed at the surface of a flat horizontal heater surrounded by an externally cooled liquid is investigated in the presence of a gravitational field. Consideration is given to the case when the stationary base state is characterized by the heat fluxes balanced at the interface between the two media. The critical value of the heat flux required for the complete suppression of the Rayleigh–Taylor instability by the phase transition has been evaluated mainly in the absence of the natural convection in the liquid layer and is found to be different from the known data obtained by approximate approaches. The case of the instability suppression in the system when long-wave disturbances have the longest lifetime is described. It has been shown that the media pressure influence on the phase transition, revealed in thin vapor films, can markedly increase the growth rate of long-wave disturbances and prevent their suppression.