Investigation on dynamic characteristics of droplet impact on surfaces with different rough microstructures based on lattice Boltzmann method

Constructing microstructures on smooth surfaces is significant for 3D printing technology and surface self-cleaning effects in engineering applications. This paper uses the lattice Boltzmann method (LBM) to study the droplet impact behavior on different microstructured surfaces: right-triangle, semicircular, and rectangular microstructures. The formulas for calculating the surface wetting characteristics of different microstructures are derived theoretically, the difference between simulation results and those from theoretical analyses is less than 5 %. The increase of the microstructure column height h may eventually lead to the disappearance of the Wenzel mode. The droplet impact on the microstructured hydrophilic surface can accelerate the droplet to the stable stage and reduce the excessive impact effect. The droplet impacts on the superhydrophobic microstructured surface can accelerate the rebound separation and shorten the time to reach the stable stage. When droplets impact the superhydrophobic surface of the right-triangle microstructure, a secondary separation phenomenon will occur, resulting in the maximum rebound height and the maximum reduction of the near-wall density. The superhydrophobic right-triangle microstructured surface can more effectively promote self-cleaning.