Levich Institute Seminar Announcement, 03/24/2009
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor Elisabeth Guazzelli
Groupe Ecoulements de Particules (GEP) IUSTI, Polytech Marseille
"Sediment Transport and Dunes in Pipe Flow"
When particle beds are submitted to shearing flows, the particles at the surface of the bed can move as soon as hydrodynamic forces acting on them exceed a fraction of their apparent weight. This situation occurs in a wide variety of natural phenomena, such as sediment transport in rivers or by air, and in industrial processes, such as hydrate or sand issues in oil production and granular transport in food or pharmaceutical industries. A very common feature that arises is the formation of ripples, i.e. small waves on the bed surface, or of dunes, i.e. larger mounds or ridges.
This talk will examine a bed constituted of sediment particles submitted to a pipe flow. It will discuss (i) the critical condition for incipient motion of the
grains, (ii) bed-load transport, and (iii) the different dune patterns that arise as the flow is increased from the laminar to the turbulent regimes. The theoretical investigation uses a two-phase
model having a granular rheology for the particulate phase. Calculations are performed numerically but also analytically in asymptotic cases. These predictions are compared to experimental results
obtained in laminar flow above a bed composed of spherical particles in a pipe.
CURRENT RESEARCH INTERESTS:
Mobile Particulate Systems and more generally Fluid Dynamics and Soft-Matter