Measuring jumps during granular chute-flows using X-ray radiography

The present paper describes laboratory tests on steady granular flows down a smooth chute using X-ray radiography. By using an original granular chute set-up with a gate at its end, standing discontinuites in height, velocity and density, namely jumps, were produced during the granular flows. The X-ray radiography was successful to get consistent measurements of the free-surface and density profiles of the flows along the chute under different flow states: the (nearly) uniform flows before the jumps, the gradually-varied flows after the jumps, and the highly non-uniform flows across the jumps. This demonstrates the efficiency of the X-ray radiography to measure granular flows.