Lun. 13/09/2021 14:00 Andromede, Bâtiment 11, Etage 3
THIÉVENAZ Virgile (University of California, Santa Barbara)
Dense suspensions and equivalent granular packings
(Matière Molle & Verres)
The viscosity of a suspension is known to diverge when the suspension becomes too dense, that is when the particle volume fraction approaches the jamming fraction. Most models used too describe this divergence are partly or fully empirical, and treat the jamming fraction as an adjustable parameter. We introduce a novel physical interpretation of the jamming fraction as the range of motion of particles. This range of motion can be computed by considering an equivalent granular packing. First, this approach provides us with a scaling law for the viscosity, which fits well the experimental measurements at low shear rate. Second, it helps understand why confined suspensions exhibit a higher viscosity. Finally, it enables to compute the viscosity of polydisperse suspensions by considering the jamming fraction of polydisperse granular packings.
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