We study – through numerical simulations – a droplet sliding over a solid substrate as a result of a simple shear flow. We use a free-energy lattice-Boltzmann (LB) scheme and compare its results with those of molecular dynamics (MD) simulations. According to the MD, at sufficiently low Reynolds and capillary numbers, the dimensionless sliding speed is a unique function of the equilibrium contact angle. Reproducing the MD results with LB simulations requires the use of a non-equilibrium boundary condition at the substrate and tuning a free parameter in the boundary condition.
- immiscible liquids
- interfacial tension
- moving contact lines
- molecular dynamics
- free-energy lattice-Boltzmann method