Levich Institute Seminar Announcement, 03/15/2005
Tuesday, 03/15/2005
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Professor Anthony Rosato
New Jersey Institute of Technology
Mechanical Engineering Department

"Migration of an Intruder in a Boundary Driven Granular Flow"


This talk discusses the behavior of a large intruder particle within a bed of uniform particles of diameter that undergo a gravity-free shear flow induced through parallel bumpy boundaries that move in opposite directions at constant velocity U. The system is studied using discrete element simulations in which particles are modeled as inelastic, frictional spheres. The flow is described by steady-state profiles of mean velocity, granular temperature, solids fraction and normal pressure. A nonuniform local shear rate, characterized by an S-shaped mean velocity profile, produces an imbalance in the contact distribution of particles in the vicinity of the walls so that they drift toward the geometric center of the flow. Results reveal the formation of convective-like structures in secondary velocity field whose wavelength decreases with effective shear rate. A large intruder Φ Ξ D/d > 1 migrates away from energetic regions adjacent to the walls and eventually becomes trapped near the mid-plane of the flow with a speed that increases with Φ and the effective shear rate ε = 2U/H. Fluctuations in the evolution of its velocity obey a power law of the form Vrmsy = C Φ-a , while fluctuations in its net force vary directly with Φ.



Computer simulations of granular and dusty flows