Scaling laws in granular flows down rough inclined planes

In this paper, new scaling properties for granular flows rough inclined planes are presented. In the dense steady uniform how regime, we have systematically measured the mean velocity of the flow as a function of the inclination of the surface theta and of the thickness h of the layer. The results obtained for different systems of beads corresponding to different surface roughness conditions are shown to collapse into a single curve when properly scaled. The scaling is based on the measurement of the minimum thickness h(stop)(theta) necessary to observe a steady uniform flow at inclination theta. From this experimental observation an empirical description for granular hows down inclined planes is proposed in terms of a dynamic friction coefficient. (C) 1999 American Institute of Physics. [S1070-6631(99)00603-0].