Publication Date


Document Type


First Advisor

Pohlman, Nicholas A.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering


Granular materials--Fluid dynamics


Simulations of granular flow assume a consistent flowing layer profile observed in circular tumblers that were half full. While the constant shear rate model predicts mixing kinematics adequately, the model has not been empirically tested in systems where the erosion from the solid body has velocity components along the dynamic angle of repose. This thesis explores experiments that analyze the relationship be- tween tumbler fill fraction and the kinematics of the erosion boundary transition into the flowing layer. Tumblers greater than 50% full have inertial velocity along the angle of repose; fill conditions less than 50% enter with velocity opposite the free surface angle. Results confirm that flowing layer chord length alone properly scales flowing layer depth only when fill fraction is near 50%; otherwise fill fraction must be considered. This is due to the streamwise velocity of particles at the erosion boundary affecting the energy balance of the system. In addition the asymmetric velocity profile derived from the non-dimensional momentum equation is confirmed for non half full systems. Lastly, linear and exponential shear models are explored and shown to be qualitatively similar; variation is only exhibited at extreme fill and positions.


Advisors: Nicholas A. Pohlman.||Committee members: Pradip Majumdar; John Shelton.||Includes bibliographical references.||Includes illustrations.


63 pages




Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type