Compound convection patterns in a layer of volatile fluid driven by a horizontal temperature gradient*

Stability of, and pattern formation in, liquid layers driven by a horizontal temperature gradient have been studied extensively in various limiting cases. In particular, in very thin liquid layers, thermocapillary stresses dominate and the instability typically leads to hydrothermal waves traveling in the direction of thermal gradient. In thicker layers, when the effect of buoyancy becomes comparable (i.e., for dynamic Bond numbers of order unity), one tends to find stationary patterns of co-rotating convection cells instead. However, what happens in the intermediate range has not been studied well. Our linear stability analysis predicted that the emerging convection pattern should be composed of hydrothermal waves on the cold side and stationary convection cells on the hot side. We confirmed the analytical predictions using numerical simulations based on a comprehensive two-sided transport model which describes a confined layer of volatile liquid in local equilibrium with its vapor at ambient conditions.