The flux properties and the inclination angle at which granular material on
inclined planes starts to slide are strongly influenced by the boundary co
nditions, such as the continuous supply of material at the upper surface or
the vibration of the bottom. Johnson et al. [P.C. Johnson, P. Nott, R. Jac
kson, J. Fluid Mech. 210 (1990) 501-535.] established a theory based on the
equations of motion for granular flow down inclined chutes with a noneffec
ted free surface. We modified the boundary conditions to take into account
energy and momentum transfer at the upper surface but we disregarded the su
pply of mass. The numerical results are compared with measurements taken fr
om a high-speed video film. (C) 2000 Elsevier Science S.A. All rights reser
ved.