Biomedical subjects

Guillemette Picard

Publications and source records attributed to Guillemette Picard.

2 recordsLinked to original sources

PubMed2005

Slow flows of yield stress fluids: Complex spatiotemporal behavior within a simple elastoplastic model.

A minimal athermal model for the flow of dense disordered materials is proposed, based on two generic ingredients: local plastic events occuring above a microscopic yield stress, and the nonlocal elastic release of the stress these events induce in the material. A complex spatiotemporal rheological behavior results, with features in line with recent experimental observations. At low shear rates, macroscopic flow actually originates from collective correlated bursts of plastic events, taking place in dynamically generated fragile zones. The related correlation length diverges algebraically at small shear rates. In confined geometries, bursts occur preferentially close to the walls, yielding an intermittent form of flow localization.

Journal Article↗

PubMed2002

Simple model for heterogeneous flows of yield stress fluids.

Various experiments evidence spatial heterogeneities in sheared yield stress fluids. To account for heterogeneities in the velocity gradient direction, we use a simple model corresponding to a nonmonotonic local flow curve and study a simple shear geometry. Different types of boundary conditions are considered. Under controlled macroscopic shear stress Sigma, we find homogeneous flow in the bulk and a hysteretic macroscopic stress-shear-rate curve. Under controlled macroscopic shear rate Gamma;, shear banding is predicted within a range of values of Gamma;. For small shear rates, stick-slip can also be observed. These qualitative behaviors are robust to changes in the boundary conditions.

Journal Article↗