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Cross-stream oscillations in the granular flow through a vertical channel

Debnath, B and Kesava Rao, K and Kumaran, V (2023) Cross-stream oscillations in the granular flow through a vertical channel. In: Journal of Fluid Mechanics, 975 .

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Official URL: https://doi.org/10.1017/jfm.2023.853


The gravity flow of a granular material between two vertical walls separated by a width is simulated using the discrete element method (DEM). Periodic boundary conditions are applied in the flow (vertical) and the other horizontal directions. The mass flow rate is controlled by specifying the average solids fraction, the ratio of the volume of the particles to the volume of the channel. A steady fully developed state can be achieved for a narrow range of, and the material is in free fall for), there are oscillations in the horizontal coordinate of the centre of mass, velocity components and stress. As decreases in the range � � � -min]]>. For an intermediate range of ( � � � -min]]>, the amplitude of the oscillations increases proportional to and the frequency appears to tend to a non-zero value as, indicating a supercritical Hopf bifurcation. The relation between the dominant frequency and the higher harmonics of the position, velocity and stress fluctuations are explained using the momentum balance. It is found that dissipation in the inter-particle and particle-wall contacts is critical for the presence of an oscillatory state. © The Author(s), 2023. Published by Cambridge University Press.

Item Type: Journal Article
Publication: Journal of Fluid Mechanics
Publisher: Cambridge University Press
Additional Information: The copyright for this article belongs to Cambridge University Press.
Keywords: Finite difference method; Hopf bifurcation, 'Dry' ; Discrete elements method; Dry granular material; Flowthrough; Granular flows; Gravity flows; Mass-flow rate; Periodic boundary conditions; Vertical channels; Vertical wall, Granular materials, amplitude; boundary condition; coordinate; discrete element method; granular medium; gravity flow; oscillation; wall
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Date Deposited: 29 Feb 2024 06:18
Last Modified: 29 Feb 2024 06:18
URI: https://eprints.iisc.ac.in/id/eprint/83739

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