Flow transitions in two-dimensional foams

Abstract

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. {\bf 69}, 636 (2005)]. Two of these regimes are identified with continuum behavior (full flow and shear-banding), and the third regime is identified as a discrete regime exhibiting extreme localization. In this paper, the discrete regime is studied in more detail using a model two dimensional foam: a bubble raft. We characterize the behavior of the bubble raft subjected to a constant rate of strain as a function of time, system size, and applied rate of strain. We observe localized flow that is consistent with the coexistence of a power-law fluid with rigid body rotation. As a function of applied rate of strain, there is a transition from a continuum description of the flow to discrete flow when the thickness of the flow region is approximately 10 bubbles. This occurs at an applied rotation rate of approximately $0.07{\mathrm{s}}^{-1}$.

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Cited by in corpus (18)

• Yield Stress Materials in Soft Condensed Matter
• Phenomenology and physical origin of shear-localization and shear-banding in complex fluids
• On the existence of a simple yield stress fluid behavior
• Shear-induced transitions and instabilities in surfactant wormlike micelles
• Rate Dependence and Role of Disorder in Linearly Sheared Two-Dimensional Foams
• Theoretical model of viscous friction inside steadily sheared foams and concentrated emulsions
• Taylor-like vortices in the shear-banding flow of giant micelles
• Couette Flow of Two-Dimensional Foams
• Flow in linearly sheared two dimensional foams: from bubble to bulk scale
• Investigation of shear banding in three-dimensional foams
• Jamming in sheared foams and emulsions, explained by critical instability of the films between neighboring bubbles and drops
• Non-axisymmetric instability of shear-banded Taylor-Couette flow
• Viscoelastic shear banding in foam
• Local Oscillatory Rheology from Echography
• A Small-gap Effective-Temperature Model of Transient Shear Band Formation During Flow
• Instantaneous Normal Modes Reveal Structural Signatures for the Herschel-Bulkley Rheology in Sheared Glasses
• Comparison of low amplitude oscillatory shear in experimental and computational studies of model foams
• The origin of the strain-rate discontinuity in 2D foam rheometry with circular geometry