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

Loading...
Thumbnail Image

Date

2012

Authors

Tang, Junyao

Advisors

Behringer, Robert P

Journal Title

Journal ISSN

Volume Title

Repository Usage Stats

711
views
536
downloads

Abstract

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) .

Department

Description

Provenance

Citation

Citation

Tang, Junyao (2012). Flow and Jamming of Granular Materials in a Two-dimensional Hopper. Dissertation, Duke University. Retrieved from https://hdl.handle.net/10161/6157.

Collections


Dukes student scholarship is made available to the public using a Creative Commons Attribution / Non-commercial / No derivative (CC-BY-NC-ND) license.