Contact line motion without slip in lattice Boltzmann simulations

We have simulated the pressure driven motion of a gas bubble immersed in a partially wetting liquid in a two-dimensional channel using the Shan and Chen multi-phase lattice Boltzmann (LB) method. Both the one-component and the two-component multi-phase models of the Shan-Chen approach have been used. The static contact angle at the fluid-solid interface was controlled by adjusting the fluid-solid interaction potential. The variation of the dynamic contact angle with the capillary number obtained from the LB simulations was compared with experimental data from the literature. Our results indicate that in the LB simulation the contact line moves over the no-slip surface due to evaporation at the nose and condensation at the tail of the bubble. This is in contrast to reality where slip at the contact line facilitates the bubble motion. We show that by controlling the extent of phase transition the simulations can be brought into close agreement with experimental data from the literature.