Mechanical and Aerospace Engineering
Department Seminar Series
Aix-Marseille University, CNRS
Shear-induced migration is a conspicuous example of the effects of irreversible dynamics in shearing flows of Stokesian, non-colloidal suspensions. It can drive particles, irreversibly, from the high to the low shear rate regions of the flow. This phenomenon has been identified in Couette viscometers but also in pressure-driven flow through a pipe or channel. It has prompted a large number of experimental studies due to the impact that such migration has on the characterisation of suspension rheology. The objective of the present work is to examine the dynamics of shear-induced migration in a pipe flow, in addition to the steady and fully developed concentration and velocity profiles which has been the focus of most previous studies. We study the large-oscillation flow of a concentrated suspension in a pipe. Particle volume fraction and particle velocity are examined through refractive index matching techniques. The particles are seen to migrate toward the center of the pipe, i.e. from the region of high to low shear-rate. The dynamics of the shear-induced migration process is analyzed and in particular compared to the prediction of the suspension balance model using realistic rheological laws.
This work is done in collaboration with Braden Snook and Jason E. Butler (University of Florida).
Élisabeth Guazzelli is Senior Researcher (Directeur de Recherche) at the CNRS (Centre National de la Recherche Scientifique). She did her graduate training in physics at the École Normale Supérieure de Fontenay aux Roses and Université Paris-Sud. Her research interests are in the field of particulate multiphase flows, such as granular media, fluidized beds, suspensions, and sedimentation. Élisabeth Guazzelli is an associated faculty at the Benjamin Levich Institute at City College of CUNY. She is a fellow of the American Physical Society and an Associate Editor of the Journal of Fluid Mechanics.