Experimental and numerical study of particles resuspension

One of the first fundamental investigations on the resuspension of micron-sized particles in shear flows probably dates back to the 1930s, when Shields reported the existence of a threshold wall shear, beyond which particle re-entrainment into the flow occurs. Improvements have since been made, yet they do not provide all ingredients for a complete description of all mechanisms occurring at the particle scale. In this work, we experimentally discover, that the inter-particle collisions are key to the resuspension of a mono-layer bed of 40 micrometer glass beads in a gas flow. Our experimental findings, supported by simulations, stress the need to account for the role of inter-particle collisions, that all models have so far neglected.