Levich Institute Seminar Announcement, 03/08/2016
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Dr. Morgane Houssais
City College of CUNY
"Complex Material Rheology in Landscape Dynamics"
Relief evolution at the Earth surface is mostly driven by mountain chains surrection and erosion and the transport of the resulting sediment. Sediment is composed of particles of wide range of size, shape, and composition, from nanometer-scale clays to meter-scale boulders; they form beds which are sheared by gravity and natural fluid (air or water) flows. As a result, when sediment is mobilized it presents complex material behavior. In this seminar, I will present experimental results on the rheology of dense packs of negatively-buoyant spheres entrained by a laminar simple-shear flow – the simplest model for fluvial sediment transport – using the technic of refractive index matching. These results confirm, for the first time, that rheological laws for homogeneous dense neutrally-buoyant suspension and granular flows both apply locally to settling particles. They also point out the need of studying further the creep regime, which emerges for local effective friction coefficient under the static friction coefficient. This challenge falls into the general effort of understanding better the deformation of nonnewtonian fluids at stresses below the yield stress, and it relates to their properties above yielding. Along the presentation I will discuss the general importance and implications of this research in earth sciences, where different flow regimes have rather been segmented — and associated to different landscapes parts — than connected to each others.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
RECENT RESEARCH INTERESTS
Common particle scale mechanisms the suspension and the dry granular rheology, granular material creep, shear thickening, granular lift and drag.