Block-to-granular-like transition in dense bubble flowsN. Vandewalle, S. Trabelsi and H. Caps
GRASP, Department of Physics B5, University of Liège B-4000 Liège, Belgium
(Received 1 July 2003; accepted in final form 5 November 2003)
We have experimentally investigated 2-dimensional dense bubble flows underneath inclined planes. Velocity profiles and velocity fluctuations have been measured. A broad second-order phase transition between two dynamical regimes is observed as a function of the tilt angle . For low values, a block motion is observed. For high values, the velocity profile becomes curved and a shear velocity gradient appears in the flow.
45.70.-n - Granular systems.
05.45.-a - Nonlinear dynamics and nonlinear dynamical systems.
81.05.Rm - Porous materials; granular materials.
© EDP Sciences 2004