Dynamics of density waves in a two dimensional funnel on an inclined plane
Groupe Matière Condensée et Matériaux (UMR 6626) ,
Université de Rennes I, 35042 Rennes Cedex, France
Accepted: 18 September 1998
Published online: 15 February 1999
We report here experiments on two-dimensional funnel flow of 1mm diameter glass beads on an inclined plane. We have investigated the properties of the flow according to the outlet size D of the funnel and the gravity. We have identified three different regimes. For small funnel outlet sizes, there is no significant change in flow density: the flow is rather steady and homogeneous. For intermediate outlet sizes (20mm< D<80mm), the flow is intermittent, consisting of spatially ordered density waves propagating upwards. At bigger outlet sizes, density waves do not exhibit any ordering and the flow dynamics becomes chaotic. In addition, we find that the flow dynamics is independent of the funnel opening angle except close to the channel flow configuration. Finally, it is stressed that the interactions between the beads and the inclined plane play a crucial role in the mechanism of formation of density waves.
PACS: 83.50.v – Deformation; material flow / 83.70.Fn – Granular solids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999