Résumé
This paper presents an investigation into drop spreading and capillary absorption at the surface of a porous substrate. Lattice Boltzmann numerical simulations are carried out at the pore level with two values of intrinsic contact angle at the liquid-gas-solid line and three values of porosity; the case of a flat solid surface is included as a reference. The numerical results show a power-law evolution of the wetted zone radius with time, both exponent and prefactor decreasing with increasing porosity. The evolution in time of the droplet height emerges from competition between pure spreading and bulk capillary imbibition in the porous medium.