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arXiv · 2105.01351

Experimental investigation and numerical modelling of density-driven segregation in an annular shear cell

Monica Tirapelle·Andrea Santomaso·Patrick Richard·Riccardo Artoni
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Abstract

Granular materials segregate spontaneously due to differences in particle size, shape, density and flow behaviour. In this paper we experimentally investigate density-difference-driven segregation for a range of density ratios and a range of heavy particle concentrations. The experiments are conducted in an annular shear cell with rotating bumpy bottom that yields an exponential shear profile. The cell is initially filled with a layer of light particles and an upper layer of heavier grains and, on top, a load provides confinement. The segregation process is filmed through the transparent side-wall with a camera, and the evolution of particle concentration in space and time is evaluated by means of post-processing image analysis. We also propose a continuum-approach to model density-driven segregation. We use a segregation-diffusion transport equation, constitutive relations for effective viscosity and friction coefficient, and a segregation velocity analogous to the Stokes' law. The model, which is validated by comparison with experimental findings, can successfully predict density-driven segregation at different density ratios and volumetric fraction.

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Monica Tirapelle, Andrea Santomaso, Patrick Richard, Riccardo Artoni. 2021-05-04. Experimental investigation and numerical modelling of density-driven segregation in an annular shear cell. https://doi.org/10.1016/j.apt.2021.02.020

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