Three-dimensional study of double droplets impact on a wettability-patterned surface

Abstract

In this paper, a three-dimensional multi-relaxation-time pseudopotential lattice Boltzmann model is adopted to study the double droplets impact on a wettability-patterned surface. The effects of several factors like the wettability difference, the Weber number and the droplet spacing on the droplet dynamic behavior are studied in detail. The numerical results show that the unbalanced Young’s force caused by the wetting difference will induce the droplets to rebound or migrate laterally toward the region with high-wettability. In addition, there exist three evolutionary phases for the double droplets impact on the wettability-patterned surface: the asymmetric spreading phase, asymmetric retracting phase, and wetting equilibrium phase. Further, when the Weber number is relatively smaller, a secondary spreading behavior could be observed which in turn causes an increase in the contact time. Finally, as far as the influence of the droplet spacing is concerned, we find that the flow patterns for different droplet spacings are largely different, and the presence of a air cavity could reduce the contact time.