Droplet impact on patterned wettable surface: Experiments and numerical analysis

Droplet impact finds enormous applications in our daily lives, ranging from raindrop impacts and pesticide spraying to corrosion of turbine blades and aircraft. Surface wettability significantly influences droplet impact dynamics, offering promises for diverse scientific research and applications. The current work studies the impact behavior of droplets striking on patterned surfaces numerically and experimentally. A three-dimensional computational model considering the conservative form of the level set method is used to simulate the droplet impact processes. The simulation results are compared with the experimental observations in the literature and the current experimental study. The effects of droplet diameter and Weber number (We) are studied. The spreading and receding morphology and subsequent accumulation of liquids on patterned wettability surfaces are discussed. Analytical models were proposed for the post-impact droplet oscillations and energy-based droplet spreading. The findings of this work demonstrate that wettability patterning can be strategically employed to manipulate droplet motion and induce controlled splitting.