Kinematics of granular material in a two-dimensional Couette shearing cell

Christopher Templeman

An investigation of the kinematics of granular material in 2D Couette shearing cell was conducted. A bimodal distribution of rigid cylindrical disks (1400 0.939±0.002 cm diameter and 237 1.248±0.001 cm diameter) were placed between an inner rotating wheel and a stationary outer ring. The system exhibited two states; a transient and a steady state. Observations of the local order of the system were made during the transient and video data acquisition was used to study the steady state. When the disks were sheared, a shear band existed adjacent to the rotating wheel that set up a velocity profile. In the steady state the velocity profile was found to be reproducible and was fit to the equation, v(r/d)=A0 exp[A1(r/d)] , where r was the width of the shearing cell, d was the diameter of a small disk and A0 and A1 were experimentally determined to be 0.5±0.3 and 1.08±0.12 respectively. The substrate under the disks was changed to determine the effect of the substrate friction on the kinematics of the disks. The three substrates used had coefficients of static friction of 0.41±0.09, 0.37±0.02, 0.23±0.05. There was no correlation found between changing the substrate and the kinematics of the system. The system behaved in a like manner with all the substrates. The results of this investigation are presented along with possible improvements and routes for further study.