A numerical study on the coefficient of restitution of wet collisions

Using smoothed particle hydrodynamics (SPH) simulations, we investigate the coefficient of restitution (COR) in wet collisions and identify a scaling law governing its behavior.

The simulations employ an updated-Lagrangian, mesh-free framework that is validated against experimental measurements.

We neglect surface tension effects since the impact conditions correspond to a moderate-to-high Weber number regime.

The COR is found to depend on the Stokes number and a dimensionless film thickness defined as the ratio of the liquid film thickness to the diameter of the impacting solid bead.

Two distinct regimes are observed, each characterized by different power-law exponents.