Flow transitions in two-dimensional foams

Flow transitions in two-dimensional foams.

For sufficiently slow rates of strain, flowing foam can exhibit inhomogeneous flows. The nature of these flows is an area of active study in both two-dimensional model foams and three dimensional foam. Recent work in three-dimensional foam has identified three distinct regimes of flow [S. Rodts, J. C. Baudez, and P. Coussot, Europhys. Lett. 69, 636 (2005)]. Two of these regimes are identified w...

Relaxation and flow in linearly sheared two-dimensional foams

We probe the relation between rheology and shear-induced relaxation in experiments on two-dimensional foams at steady shear. The characteristic relaxation time tr, which we extract from the non-affine part of the bubble displacements, scales non-linearly with the local strain rate γ̇. In particular, the relative strength of the non-affine part grows when γ̇ → 0 —hence the foam flow is not quasist...

Screening in two-dimensional foams

a Institute of Mathematics and Physics, Aberystwyth University, Ceredigion SY23 3BZ, United Kingdom, Email: [email protected] b Laboratoire de Spectrométrie Physique, UMR5588, CNRS-Université Grenoble I, B.P. 87, F-38402 Martin d’Hères Cedex, France c Instituto de Ciência e Engenharia de Materiais e Superficies and Departamento de Engenharia de Materiais, Instituto Superior Técnico, Avenida Rovi...

Phase Transitions in Foams

Phase transitions in two-dimensional traffic-flow models.

We introduce two simple two-dimensional lattice models to study traffic flow in cities. We have found that a few basic elements give rise to the characteristic phase diagram of a first-order phase transition from a freely moving phase to a jammed state, with a critical point. The jammed phase presents new transitions corresponding to structural transformations of the jam. We discuss their relev...