Europhys. Lett.
Volume 65, Number 3, February 2004
Page(s) 316 - 322
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 01 January 2004
Europhys. Lett., 65 (3) , pp. 316-322 (2004)
DOI: 10.1209/epl/i2003-10103-6

Block-to-granular-like transition in dense bubble flows

N. 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 $\theta$. For low $\theta$ values, a block motion is observed. For high $\theta$ 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