Rheology of 2D liquid foams: the bubble model
Vincent Langlois
Fluid.DTU
Abstract:
Several experiments have recently raised many questions concerning flows of 2D foams (i.e. confined monolayers of air bubbles): what is the stress-strain relation ? when does flow localization occur, and is there a yield shear rate ? how do disorder, polydispersity and liquid fraction influence the rheology ?
To address these questions we have performed numerical simulations based on the bubble model rather than the quasi-static approach. We show that a model incorporating only linear local forces can give rise to a non-linear Herschel-Bulkley behaviour, thus providing the link between local and continuum descriptions of a foam. Our simulations also account for the apparition of shearbands when wall slip is added, and predict the existence of a dynamic dilatancy effect. Finally, we show how it can be successfully applied to various flow geometries.