Foams in a rotating drum: An analogy with granular materials

Rotating drums are usually used to study the flowing properties of granular materials. Here, we report experiments performed in a drum made of a circular Hele-Shaw cell filled with a monodisperse foam and its surfactant solution. The cell is placed vertically and rotated around its center with an angular velocity co. The rotation of the cell modifies the foam properties and therefore influences its response to the external strain. The observed foam behavior is similar to granular media in several aspects. Using tools developed for granular materials, we characterize the foam evolution in terms of a dimensionless viscous number If and we compare the foam rheology to the theory developed for the immersed granular material rheology. (C) 2015 Elsevier B.V. All rights reserved.