Bubble and granular flows: differences and similarities

We have experimentally studied the dense flow of identical bubbles below planes inclined at an angle theta. The flow is driven by the fast motion of dislocations. As a function of the density of dislocations (controlled by the parameter theta), a transition occurs between a simple collective block motion and a granular-like surface flow regime. (C) 2004 Elsevier B.V. All rights reserved.