Particle–plate collisions across varying liquid layer depths

This study systematically investigates the dynamics of particle–plate collisions across varying liquid layer depths, aiming to elucidate the influence of liquid layer thickness on impact processes, rebound behavior, and impact forces. Using a custom-built experimental setup combining high-speed imaging and multi-point dynamic pressure sensors, the effects of particle size, initial velocity, and liquid layer thickness on collision dynamics were examined. Results reveal that the liquid layer depth significantly alters liquid bridge morphology and rebound characteristics. For thin liquid layers (h/d < 0.4), collisions are dominated by lubrication and capillary effects, resulting in high restitution coefficients (e). As the liquid layer thickness increases to the shallow regime (0.4 ≤ h/d ≤ 1.2), e decreases sharply due to enhanced viscous dissipation and inertial damping. An exponential decay model fitted to the experimental data shows that e decreases exponentially with increasing h/d, with the decay rate closely related to the initial impact velocity. Additionally, measurements of impact forces in the liquid layer show that thicker liquid layers more effectively cushion the impact, resulting in significantly reduced forces. This work enhances understanding of the role of liquid layer thickness in particle–plate collisions, with implications for multiphase flow transport and engineering design.