Impact dynamics of multiple droplets on lightweight surface

Based on the surface interface model of the superhydrophobic cantilever dragonfly wing surface (SCDWS), the process of multi-droplet impact on the lightweight surface and the motion of adjacent droplets are observed. The influence of the dimensionless horizontal and vertical spacing of adjacent droplets as well as the impact velocity on the droplet interactions is analyzed. And the unidirectional migratory motion of the droplets, interactions among multiple droplets and the self-propelled effect are explored. The results show that liquid-bridge connection and droplet fusion phenomena occur in adjacent droplets during multi-droplet impact, and the coalescence of adjacent droplets generates sub-droplets. The droplet spreading coefficient decreases and then increases at different horizontal spacings, and eventually remains near a constant value. As the horizontal spacing between neighboring droplets decreases, the droplet spreading coefficient increases. Under the oscillation effect on the cantilever surface, the droplet undergoes self-driven rebounding and jumping, facilitating its directional transport.