The Flow Structure near the Leading Edge of a Liquid Layer Spreading Along a Superhydrophobic Surface

Flows in the vicinity of the wetting front of a viscous liquid film spreading in a gravity field along inclined, vertical, and horizontal superhydrophobic surfaces (SHS) with a slip boundary condition (Navier condition) are considered. Within the framework of the Stokes film approximation with local allowance for the longitudinal pressure gradient and (or) surface tension, the method of matched asymptotic expansions is used to derive equations describing self-similar solutions for the film surface shape and the flow parameters in the vicinity of a moving wetting front on the SHS. For different surface inclination angles to the horizon, the effect of the slip coefficient on the film surface shape, the dimensions of the region where the longitudinal pressure gradient and (or) surface tension are significant, and the flow structure in this region is investigated based on asymptotic and numerical analysis.