Granular materials exhibit several regimes of behavior: plastic, inertial,
fluidized, and entrained how but not all materials can pass through all the
se states. Our concern is with the criteria that determine the transition f
rom one regime to another and with the boundaries to the various flow regim
es that these criteria define. We have focused on fine, cohesive powders, w
here the interparticle cohesive force dominates over the gravitational forc
e. The experiments to analyze this topic have been performed using a rotati
ng drum device.