Influence of Initial Velocity and Lateral Sliding Angle on Coalescence-Induced Jumping of Nanodroplets on Superhydrophobic Surfaces

This study employs molecular dynamics simulations to comprehensively investigate nanoscale droplet coalescence-induced jumping dynamics on superhydrophobic surfaces, focusing on the coupled effects of initial Weber numbers (We) and lateral sliding angles (θ). The research systematically analyzes dimensionless jumping velocity, jumping time, droplet centroid trajectories, droplet deformation (length-to-height ratio), and average liquid bridge growth rates under varying conditions. Results reveal that smaller lateral angles (0°, 30°) favor higher vertical jumping velocities and stable droplet trajectories at lower Weber numbers, with clear adherence to inertia-capillary scaling laws. Conversely, larger lateral angles (60°, 90°) result in substantial reductions in vertical jumping velocity due to increased lateral momentum and enhanced horizontal spreading. The novel energy analysis illustrates that the efficiency of kinetic energy conversion significantly decreases as lateral angles and Weber numbers increase, primarily due to intensified internal shear dissipation and lateral momentum dispersion. This comprehensive analysis deepens the understanding of nanoscale droplet coalescence dynamics and provides crucial insights for optimizing droplet-based thermal management and surface technologies.