Effects of viscosity in granular flows simulated in a centrifugal acceleration field

Centrifuge modelling is increasingly employed as an experimental tool for the simulation of dry and wet granular flows, providing good agreement in the representation of highly stress-dependent materials. However, the scaling relations of the interstitial fluid remain a challenging task, focusing on the matching of model and prototype processes. In this paper we present four different techniques for the simulation of the interstitial fluid (i.e. water W, water-glycerine W-G, water-methylcellulose W-M, and water-kaolin W-K). The fluid is mixed with a granular material, flowing down an inclined plane in a model tested in a drum or beam centrifuge, respectively. The granular flow behaviour developed in each case is compared in terms of the flow height, velocity and flow regimes, according to dimensional scaling. We note that in both centrifuge configurations, different flow regimes, such as inertial, collisional, or macro-viscous, can be observed, depending on the careful selection of particle size, fluid viscosity, flow rate and slope dimensions.