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Subdiffusion model for granular discharge in a submerged silo

Miles Morgan, David William James Orcid Logo, Martin Monloubou, Kristian S. Olsen, Bjornar Sandnes Orcid Logo

Physical Review E, Volume: 104, Issue: 4

Swansea University Authors: Miles Morgan, David William James Orcid Logo, Martin Monloubou, Bjornar Sandnes Orcid Logo

Abstract

Silo discharge has been extensively studied for decades although questions remain regarding the nature of the velocity eld, particularly for submerged systems. In this work, uid-driven granular drainage was performed in a quasi-2D silo with grains submerged in uid. While the observed Gaussian veloci...

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Published in: Physical Review E
ISSN: 2470-0045 2470-0053
Published: American Physical Society (APS) 2021
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa58506
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Abstract: Silo discharge has been extensively studied for decades although questions remain regarding the nature of the velocity eld, particularly for submerged systems. In this work, uid-driven granular drainage was performed in a quasi-2D silo with grains submerged in uid. While the observed Gaussian velocity proles were generally consistent with current diffusion models, the diffusion length was found to signicantly decrease with height in contrast to the increases previously seen in dry silos. We propose a new phenomenological anomalous diffusion model for the spreading of the flow upwards in the cell, with the uid-driven flows we study here falling in the category of subdiffusive behaviour. As the viscous characteristics of the system were amplied, the diffusion length increased and the shape of the owing zone in the silo changed, deviating further from the parabolic form predicted by traditional normal diffusion models, in effect becoming more subdiffusive as quantied by a decreasing diffusion exponent.
College: Faculty of Science and Engineering
Funders: This work was supported by the Engineering and Physical Sciences Research Council EPSRC Grant No. EP/S034587/1. K.S.O. acknowledges support from the Research Council of Norway through the Center of Excellence funding scheme, Project No. 262644 (PoreLab).
Issue: 4