Particle-size segregation patterns in a partially filled triangular rotating drum

Maguire, E. S. F., Barker, T., Rauter, M., Johnson, C. G. and Gray, J. M. N. T. 2024. Particle-size segregation patterns in a partially filled triangular rotating drum. Journal of Fluid Mechanics 979 , A40. 10.1017/jfm.2023.1022

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Abstract

In this paper a fully coupled particle-size segregation model for granular flows (Barker, Rauter, Maguire, Johnson and Gray, J. Fluid Mech., vol. 909, 2021, A22) is used to simulate the development of the patterns in a triangular rotating drum. The results are compared to the experimental patterns with bidisperse and tridisperse granular mixtures, and with varying compositions and fill heights. In all cases the agreement between the simulations and experiments is remarkably good. The experimental patterns are generated in a narrow gap between transparent front and back sidewalls. These prevent three-dimensional motion, but also impose friction on the flow, making it thinner and faster than it would otherwise be. This promotes segregation, as it simultaneously increases the shear rate and reduces the local pressure. To obtain the correct flow dynamics and segregation, width-averaged sidewall friction is incorporated into the two-dimensional simulations, which are performed in OpenFOAM©. The free-surface avalanche forms a boundary layer within which all the segregation occurs. Material in the lower reach of the avalanche is continuously deposited into an underlying solid body of grains, which rotates with the drum, and is eventually re-entrained into the avalanche along its upper reach. The changing geometry of the granular region (as the drum rotates) implies that the avalanche is constantly adjusting its length, position and depth. This generates a complex quasi-periodic flow, which when combined with particle-size segregation generates amazing patterns in the solid rotating granular body after only two drum rotations.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Mathematics
Subjects:	Q Science > QA Mathematics Q Science > QC Physics
Publisher:	Cambridge University Press
ISSN:	0022-1120
Date of First Compliant Deposit:	30 November 2023
Date of Acceptance:	27 November 2023
Last Modified:	09 Nov 2024 10:30
URI:	https://orca.cardiff.ac.uk/id/eprint/164414

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