Dense granular flow — A collaborative study

•Dense granular rheology was investigated via academic–industrial collaboration.•Jamming, force chains and velocity fluctuations were investigated in a 2D hopper.•Bulk rheology at higher shear rates was investigated in a 3D axial Couette.•Models were used to investigate across scales of particles, force-chains, and bulk granular flow.•Details of particle interaction models are critical to dense rheology prediction.

The International Fine Powder Research Institute (IFPRI) has funded an extensive program in dry powder and granular flows, including a focused study on dense flows of interest to a range of industrial handling and process unit operations, especially dense flows at relatively high shear rates. The dense flow program included experimental studies of granular rheology in 3D axial Couette and 2D hopper geometries, wherein the effect of force chains and jamming interactions were investigated as relevant to flow, stress and packing dynamics. The program cumulated in a collaborative study funded by the NSF, wherein a group of academic collaborators was invited to model experimental systems used in IFPRI-sponsored projects. This paper provides a summary of the IFPRI program, details of the collaborative modeling study, and perspective on what is needed to progress the work further.

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