Discrete element simulation of dense granular flow in a modified Couette cell

Large-scale three dimensional Discrete Element simulations of granular flow in a modified split-bottom Couette cell for packs of up to 180, 000 mono-disperse spheres are presented and compared with experiments. We find that the velocity profiles collapse onto a universal curve not only at the surface but also in the bulk of the pack until slip between layers becomes significant. In agreement with experiment, we find similar relations between the cell geometry and parameters involved in rescaling the velocities at the surface and in the bulk. Likewise, a change in the shape of the shear zone is observed as predicted for tall packs once the center of the shear zone is correctly defined; although the transition does not appear to be first order. Finally, the effect of cohesion is considered as a means to test the theoretical predictions. © 2005 Taylor & Francis Group.