title: Dense bubble flow in a silo: an unusual flow of a dispersed medium.
abstract: The dense flow of air bubbles in a two-dimensional silo (through an aperture D) filled with a liquid is studied experimentally. A particle tracking technique has been used to bring out the main properties of the flow: displacements of the bubbles, transverse, and axial velocities. The behavior of the air bubbles is observed to present similarities with nondeformable solid grains in a granular flow. Nevertheless, a correlation between the bubble velocities and their deformations has been evidenced. Moreover, a new discharge law (Beverloo like) must be considered for such a system, where the flow rate is observed to vary as D(1/2) and depends on the deformability of the particles.
authors.affiliation: Group for Research and Applications in Statistical Physics (GRASP), Institut de Physique B5a, Université de Liège, Belgium.
authors.forename: Yann
authors.initials: Y
authors.lastname: Bertho
authors.forename: Christophe
authors.initials: C
authors.lastname: Becco
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vandewalle