effect of surface topology and wettability on impacting droplet dynamics at moderate reynolds numbers

The present work aims to investigate the effect of surface topology and wettability on the impacting droplet dynamics at different flow conditions. a multiphase lattice boltzmann method (lbm) is employed for the simulation of interfacial dynamics. firstly, the results obtained based on the present method for some benchmark two-phase flow problems are validated. then, three surface topologies, including a flat substrate, semicircular cavity, and semicircular bump, are considered to get insight into the physical treatment of the impacting droplet. the present study shows that although the surface topology affects the spreading and rebounding processes of the impacting droplet, the hydrophilicity plays a significant role in the final form of the liquid phase and dictates a similar treatment for all the studied topologies. considering different sizes for the bump, it is found that the shape of the droplet deforms almost the same immediately after the impaction for all the bump sizes and the spreading process is not affected by the wettability. however, the receding dynamics is significantly affected by the bump size and the wetting condition of the bump surface. it is found that the contact time is minimized by increment the bump size and hydrophobicity of the surface.