title: Transient shear banding in a simple yield stress fluid.
abstract: We report a large set of experimental data which demonstrates that a simple yield stress fluid, i.e., which does not present aging or thixotropy, exhibits transient shear banding before reaching a steady state characterized by a homogeneous, linear velocity profile. The duration of the transient regime decreases as a power law with the applied shear rate γ. This power-law behavior, observed here in carbopol dispersions, does not depend on the gap width and on the boundary conditions for a given sample preparation. For γ≲0.1  s(-1), heterogeneous flows could be observed for as long as 10(5)  s. These local dynamics account for the ultraslow stress relaxation observed at low shear rates.
authors.affiliation: Université de Lyon, Laboratoire de Physique, Ecole Normale Supérieure de Lyon, CNRS UMR 5672, 46 Allée d'Italie, 69364 Lyon cedex 07, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Divoux
authors.forename: David
authors.initials: D
authors.lastname: Tamarii
authors.forename: Catherine
authors.initials: C
authors.lastname: Barentin
authors.forename: Sébastien
authors.initials: S
authors.lastname: Manneville