Drop deposition on wetted surface

When a liquid drop is gently deposited on a miscible thin liquid film, the coalescence dynamics is driven by the lubrication of both the gas interlayer and the liquid film. It induces in particular a slip velocity at the film-air interfaces that accelerates the coalescence process by comparaison with deposition on a solid substrate. Here, we develop and investigate numerically a model based on the coupling of two lubrication equations with the drop deformation. We observe interfaces deformation in good agreement with existing experiments. Finally, we characterize how the coalescence is influenced by the slipping of the lubrication layer, through the analysis of the contact time.