Yield drag in a two-dimensional foam flow around a circular obstacle: Effect of liquid fraction

Abstract

We study the two-dimensional flow of foams around a circular obstacle within a long channel. In experiments, we confine the foam between liquid and glass surfaces. In simulations, we use a deterministic software, the Surface Evolver, for bubble details and a stochastic one, the extended Potts model, for statistics. We adopt a coherent definition of liquid fraction for all studied systems. We vary it in both experiments and simulations, and determine the yield drag of the foam, that is, the force exerted on the obstacle by the foam flowing at very low velocity. We find that the yield drag is linear over a large range of the ratio of obstacle to bubble size, and is independent of the channel width over a large range. Decreasing the liquid fraction, however, strongly increases the yield drag; we discuss and interpret this dependence.

References in corpus (5)

• Relaxing in foam
• Two dimensional foam rheology with viscous drag
• Stokes experiment in a liquid foam
• Comparison between step strains and slow steady shear in a bubble raft
• Mechanical probing of liquid foam aging

Cited by in corpus (4)

• Two-dimensional flow of foam around a circular obstacle: local measurements of elasticity, plasticity and flow
• Theoretical model of viscous friction inside steadily sheared foams and concentrated emulsions
• Topological and geometrical disorder correlate robustly in two-dimensional foams
• Comparison of low amplitude oscillatory shear in experimental and computational studies of model foams