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Flow and Jamming of Granular Materials in a Two-dimensional Hopper

dc.contributor.advisor Behringer, Robert P Tang, Junyao 2013-01-16T20:28:53Z 2013-07-15T04:30:05Z 2012
dc.description.abstract <p>Flow in a hopper is both a fertile testing ground for understanding fundamental granular flow rheology and industrially highly relevant. Despite increasing research efforts in this area, a comprehensive physical theory is still lacking for both jamming and flow of granular materials in a hopper. In this work, I have designed a two dimensional (2D) hopper experiment using photoelastic particles ( particles' shape: disk or ellipse ), with the goal to build a bridge between macroscopic phenomenon of hopper flow and microscopic particle-scale dynamics. Through synchronized data of particle tracking and stress distributions in particles, I have shown differences between my data of the time-averaged velocity/stress profile of 2D hopper flow with previous theoretical predictions. I have also demonstrated the importance of a mechanical stable arch near the opening on controlling hopper flow rheology and suggested a heuristic phase diagram for the hopper flow/jamming transition. Another part of this thesis work is focused on studying the impact of particle shape of particles on hopper flow. By comparing particle-tracking and photoelastic data for ellipses and disks at the appropriate length scale, I have demonstrated an important role for the rotational freedom of elliptical particles in controlling flow rheology through particle tracking and stress analysis. This work has been supported by International Fine Particle Research Institute (IFPRI) .</p>
dc.subject Physics
dc.subject Civil engineering
dc.subject Chemical engineering
dc.subject Ellipse
dc.subject Granular Flow
dc.subject Granular Materials
dc.subject Hopper Flow
dc.subject Jamming
dc.title Flow and Jamming of Granular Materials in a Two-dimensional Hopper
dc.type Dissertation
dc.department Physics
duke.embargo.months 6

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