Simulation of flow and heat transfer in a liquid drop sliding underneath a hydrophobic surface

Clusters of liquid drops growing and moving on physically or chemically textured surfaces are encountered in dropwise mode of vapor condensation. This process can be sustained only if the surface integrity is maintained over a long period of time. Surface features are altered when sliding drops leach away the promoter layer. In the absence of chemical reactions between the promoter and the condensing liquid, the wall shear stress is the primary parameter controlling the physical leaching. In turn, wall shear stress depends on the relative speed between the drop and the substrate surface and the shape of the drop. Given a wall shear stress distribution for individual drops, the net effect of an ensemble of them during continuous quasi-steady state dropwise condensation can be determined using the population density of drops.