Shear thickening and migration in granular suspensions

Abdoulaye Fall (1, 2) , Anael Lemaitre (3) , François Bertrand (4) , Daniel Bonn (2, 5) , Guillaume Ovarlez (3)

1 navier umr 8205 - Laboratoire Navier
2 VAN DER WAALS-ZEEMAN INSTITUTE - University of Amsterdam Van der Waals-Zeeman Institute
3 Rhéophysique
4 Physique des milieux poreux
5 LPS - Laboratoire de Physique Statistique de l'ENS

We study the emergence of shear thickening in dense suspensions of non-Brownian particles. We combine local velocity and concentration measurements using Magnetic Resonance Imaging with macroscopic rheometry experiments. In steady state, we observe that the material is heterogeneous, and we find that that the local rheology presents a continuous transition at low shear rate from a viscous to a shear thickening, Bagnoldian, behavior with shear stresses proportional to the shear rate squared, as predicted by a scaling analysis. We show that the heterogeneity results from an unexpectedly fast migration of grains, which we attribute to the emergence of the Bagnoldian rheology. The migration process is observed to be accompanied by macroscopic transient discontinuous shear thickening, which is consequently not an intrinsic property of granular suspensions.

Mots clés: Shear thickening; suspension; granular material; migration

Domaines: Matière Molle [cond-mat.soft]

Abdoulaye Fall, Anael Lemaitre, François Bertrand, Daniel Bonn, Guillaume Ovarlez. Shear thickening and migration in granular suspensions. Physical Review Letters, 2010, 105, pp.268303. ⟨10.1103/PhysRevLett.105.268303⟩. ⟨hal-00490742v2⟩