Dynamics and Rheology of Hopper Flow: Two and Three Dimensions, Effects of Particle Shape and Cohesion

Publication Reference: 
Author Last Name: 
Robert P. Behringer
Report Type: 
ARR - Annual Report
Research Area: 
Powder Flow
Publication Year: 
Publication Month: 
United States

Over the past several years, work at Duke has focused on understanding jamming and flow properties in a quasi-2D hopper. During that time, we have carried out extensive measurements to characterize the basic physics of hopper flow, including measurements of jamming probabilities, flow rates, velocity fields, and force fields. We have developed a model that describes the observed jamming statistics and that allows additional insight into the physical processes associated with jamming and flow. This work has been described in previous IFPRI reports, and is not repeated here.

New work has four goals which are extending the previous work in directions that address both underlying fundamental science and also help to better inform jamming in flows that occur in practical situations. These goals include: 1) Implementing the IFPRI-NSF collaboratory project; 2) Obtaining quantitative measures of fluctuations, diffusion, and correlations (these play key role in setting the flow properties); 3) Extending photoelastic studies of jamming flow to: a) flows of non-spherical, particles, b) quasi-3D, flows, and c) flows of particles with cohesion; 4) Extending hopper flows to fully 3D using laser-scanning and x-ray fluoroscopy for imaging. In three of these areas, we have substantive results. In the fourth, we developing new experiments, and new results should be available soon. I also organized the IFPRI AGM in June of 2011, which took place at Chapel Hill, NC. This meeting was followed by a meeting of participants in the IFPRI-NSF collaborator project.