Highly resolved index-matching techniques are used to measure the local particulate volume fraction in a wide-gap Taylor–Couette configuration. We find that the fully developed concentration profiles are well predicted by the suspension balance model of Nott & Brady. Moreover, we provide systematic measurements of the migration strain scale and of the migration amplitude which highlight the limits of the suspension balance model predictions (more here 2019_sarabian_jfm).
Le rhé-épaississement est un phénomène observé dans certaines suspensions denses de particules. Il consiste en une augmentation parfois brutale de leur viscosité lorsqu’elles sont soumises à une forte contrainte. Ce comportement, très utile pour certaines applications technologiques, peut aussi s’avérer problématique dans certains processus industriels. Longtemps resté une énigme, le rhé-épaississement est désormais décrit de façon cohérente par le modèle de transition frictionnelle. Cet article présente ce modèle ainsi que les études numériques et expérimentales qui le valident. Sont ensuite abordées différentes perspectives d’applications offertes par la compréhension de ce phénomène. [2018_Clavaud_TechIngé]
A short review (in French) of my work over the past decade (2018_HDR_Metzger).
We provide acurate measurements of the flow field around a single sphere sheared in a yield stress fluid and discuss the interaction between two spheres, particularly, we show that the fore-aft asymmetry depends on the Deborah number, Bingham number, shear history, initial offset and roughness of the particles. More here 2018_Sarah_2parts.
Here we present high resolution experiments allowing for the precise quantication of the evolution of concentration distributions of a single lamella experiencing diffusion, stretching and aggregation with other lamellae [2018_Lamella_Souzy].
-Communiqué de Presse du CNRS.
-Article dans Sciences et Avenir.
-Article dans PNAS (2017_PNAS_Clavaud).
The sudden and severe increase in the viscosity of certain suspensions above an onset stress is one of the most spectacular phenomena observed in complex fluids. This shear thickening, which has major implications for industry, is a long-standing puzzle in soft-matter physics. Recently, a frictional transition was conjectured to cause this phenomenon. Using experimental concepts from granular physics, we provide direct evidences that such suspensions are frictionless under low confining pressure, which is key to understanding their shear thickening behavior. More from PNAS here (2017_PNAS_Clavaud)
