Novel Shear Banding Phenomenon Probes Soap Film Friction

Abstract

We have generated a novel form of shear banding in a 2D foam and measured the relative magnitude of drag forces on soap films at different lubrication layers. We injected air part way along a flowing bubble field in a narrow Hele-Shaw cell. The injected air inflates bubbles as they flow by, and these bubbles form a shear band down the middle of the Hele-Shaw cell. This channel appears to select a height that minimizes the total dissipation. Fitting data to a simple theoretical model, we show that the drag force on a soap film in contact with the wetting layer on a plate of glass is two orders of magnitude larger than the drag on a soap film in contact with another free soap film.

arXiv commentRevised for submission, 05/15/07

References in corpus (4)

• Deformation and flow of a two-dimensional foam under continuous shear
• Local Stress Relaxation and Shear-banding in a Dry Foam under Shear
• Viscous force exerted on a foam at a solid boundary : influence of the liquid fraction and of the bubble size
• Experimental evidence of flow destabilization in a 2D bidisperse foam