1011.0521 (Sylvain Bénito et al.)

Non-linear oscillatory rheological properties of a generic continuum
foam model: comparison with experiments and shear-banding predictions    [PDF]

Sylvain Bénito, François Molino, Charles-Henri Bruneau, Thierry Colin, Cyprien Gay

The occurence of shear bands in a complex fluid is generally understood as resulting from a structural evolution of the material under shear, which leads (from a theoretical perspective) to a non-monotonic stationnary flow curve related to the coexistence of different states of the material under shear. In this paper we present a framework for shear-banding in a particular class of complex fluids, namely foams and concentrated emulsions, which differ from other fluids in two important ways. First, the appearance of shear bands is shown to be possible without any intrinsic physical evolution of the material (e.g. via a parameter coupled to the flow such as concentration or entanglements). Secondly, the appearance of shear bands depends on the initial conditions, i.e., the preparation of the material. In other words, it is history dependent. This behaviour relies on the tensorial character of the underlying model (2D or 3D) and is triggered by an initially inhomogeneous strain distribution in the material.

View original: http://arxiv.org/abs/1011.0521