Karen E. Daniels and R. P. Behringer

Shearing and order in vibrationally fluidized 3D granular flows

Abstract: We will present initial results from a 3D annular shearing experiment which can be vibrationally excited from below. This provides two separate means of injecting energy into the system, and we are able to study the interaction of the two effects in the formation of shear bands. Experiments are performed with both mono- and poly-disperse spheres over a range of packing fractions. With increasing shear rate, we see a change in the shape of the shear band accompanied by a transition to decreased order of the mono-disperse particles. We will present velocity profiles and distributions based on particle tracking, providing insight into the statistical properties of shear systems. In addition, we measure corresponding local forces due to the presence of shifting force chains. This work has been support by the NASA Microgravity Program, under grant NAG3-2372.