Local flow structure and microdroplet trajectories near the boundary of a dry patch.

For the past few decades, there have been many studies of evaporation near contact lines where solid substrates and liquid-gas interfaces meet. The focus of our investigation is on local solutions near a contact line, which is the boundary of a dry patch. We consider a single, circular dry patch that has been formed in an evaporating liquid layer on a flat heated substrate. Flow is induced by evaporation and thus depends on the distribution of vapor concentration in moist air. We use Tranter’s method to solve the diffusion equation for vapor concentration in the domain above the liquid layer. Evaporative flux at the interface near the contact line and the corresponding local flow structure are determined based on this solution. The trajectories of microscale liquid droplets in vicinity to the contact line are assessed using different approximations for the aerodynamic drag force. Furthermore, the comparison of experimental and numerical findings is highlighted.