The dilute turbulent steady-state gas-particle flows in flat horizontal channels with different wall surface roughness are considered. The kinetic theory of granular flows has been employed for modeling. The new approach to defining boundary conditions for a solid phase, which is based on the tangential restitution coefficient, has been applied. The model has been validated by comparison of the computed data with the experimental results. (C) 2004 Elsevier Ltd. All rights reserved.