Lattice Boltzmann modeling of droplet impact on moving superhydrophobic wall.

This article focuses on the dynamics of droplets impacting moving superhydrophobic walls using a three-dimensional non-orthogonal multiple-relaxation-time lattice Boltzmann method (NMRT-LBM) that incorporates contact angle hysteresis. The study finds that contact time decreases exponentially with increasing wall velocity but is independent of the Weber number, while both the maximum spreading length and horizontal displacement increase with wall velocity and Weber number. Energy analysis reveals that the droplet impact process can be divided into spreading, retraction, and detachment stages, with only the detachment stage influenced by wall velocity; internal vortices cause kinetic energy to remain nonzero at maximum spreading. Force analysis shows that the tangential force depends on both wall velocity and Weber number, following a derived scaling law, whereas the normal force is independent of wall velocity but varies with Weber number, exhibiting two peaks related to inertial and surface tension effects. These results enhance understanding of droplet behavior on moving superhydrophobic surfaces, with future work suggested on more complex and non-uniform wettability walls.