ON PRESSURE AND VELOCITY BOUNDARY-CONDITIONS FOR THE LATTICE BOLTZMANN BGK MODEL

Pressure (density) and velocity boundary conditions are studied for 2- D and 3-D lattice Boltzmann BGK models (LBGK) and a new method to spec ify these conditions is proposed. These conditions are constructed in consistency with the wall boundary condition, based on the idea of bou nceback of the non-equilibrium distribution. When these conditions are used together with the incompressible LBGK model [J. Stat. Phys. 81, 35 (1995)] the simulation results recover the analytical solution of t he plane Poiseuille flow driven by a pressure (density) difference. Th e half-way wall bounceback boundary condition is also used with the pr essure (density) inlet/outlet conditions proposed in this paper and in Phys. Fluids 8, 2527 (1996) to study 2-D Poiseuille flow and 3-D squa re duct flow. The numerical results are approximately second-order acc urate. The magnitude of the error of the half-way wall bounceback boun dary condition is comparable with that of other published boundary con ditions and it has better stability behavior. (C) 1997 American instit ute of Physics.