Wall boundary conditions in the lattice Boltzmann equation method for nonideal gases

Wall boundary conditions for the lattice Boltzmann equation (LBE) method for nonideal gases proposed by Lee and Fischer [Phys. Rev. E 74, 046709 (2006)] are examined. The LBE simulations of the contact line are typically contaminated by small but strong counter-rotating parasitic currents near solid surfaces. We find that these currents can be eliminated to round-off if the potential form of the intermolecular force is used with the boundary conditions based on the wall energy approach and the bounce-back rule. Numerical tests confirm the elimination of the parasitic currents in the vicinity of the contact line and the agreement of the calculated density, excess mass, and contact angle at the solid surfaces with theory.