Behavior of flowing granular materials under variable g

We consider the impact of the effective gravitational acceleration geff on gravity-driven granular shear flow utilizing a tumbler of radius R rotating at angular velocity ω when geff is varied up to 25 times the gravitational level on Earth in a large centrifuge. The Froude number Fr= ω2 R geff is shown to be the proper scaling to characterize the effect of gravity on the angle of repose of the flowing layer. Likewise, transitions between flow regimes depend on Fr. Furthermore, the thickness of the flowing layer is independent of the g level. These results provide a starting point for understanding granular flows on planetary bodies with geff different than on Earth for application to planetary exploration and formation of geologic features.