The dynamic behavior of a self-propelled droplet on a conical fiber: A lattice Boltzmann study

In this paper, the dynamic behavior of a self-propelled droplet along conical fiber is simulated by using an improved lattice Boltzmann color-gradient method. This method developed on basis our recently density ratio model [Zhang et al., Int. Commun. Heat Mass Transfer, 137, 106284 (2022).], but wetting boundary condition added to account for moving contact line arbitrary solid surface. First, validated against analytical shapes and angles droplets surrounded matrix fluids different densities flat spherical surfaces, spontaneous transport fiber. then adopted systematically study effects Bond number (Bo), surface wettability (θ), cone hemi-angle (α), volume behavior. each case, results show that climbing velocity first increases decreases, fluctuation observed, which due apparent receding advancing do not simultaneously reach equilibrium angle. As increases, height monotonically increases. Bo or θ area both decrease. We also found decreases with α, its maximum reached around α=2.5°.