We construct constitutive relations for friction stress, slide stress and collision stress of cohesionless granular flows. We propose that the friction stress and slide stress could be neglected when tau(c)/tau(c)< 0.02, where tau(c) represents the interval time experienced by a given particle between two consecutive binary collisions and T, the particle relaxation time. We applied these constitutive relations to a simulation of solid-liquid flow in an inclined chute and found the simulation results agree with experimental data. (c) 2005 Elsevier B.V. All rights reserved.