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Communication Dans Un Congrès Année : 2024

Elongated Grains in Silos: A 3D Odyssey through Non-linear Flow Variations

Résumé

Three-dimensional contact dynamics simulations are used to study the flow properties of elongated grains in a silo. The grains have a sphero-cylinder shape described by their aspect ratio, which varies from 1 (sphere) to 5 for a thin elongated grain. To ensure accurate statistics, a "perpetual" discharge is simulated for different orifice sizes by 1) reintroducing the exiting grains at the top of the silo and 2) implementing a procedure to break arches when the flow comes to rest, especially for small orifice sizes. As a general observation, when the flow rate Q is plotted as a function of orifice size, it follows a Beverloo-like curve for all shapes. In contrast, for a given orifice size, the flow rate Q is found to vary non-linearly with grain elongation: It first increases to a maximum and then decreases with increasing elongation. Both the packing fraction and velocity profiles are found to be self-similar near the orifice when normalised to the maximum packing fraction and velocity measured at the center of the orifice, respectively. From these profiles, a 3D theoretical expression, inspired by the work of Janda et al [Phys. Rev. Lett. 108, 248001], for the evolution of the flow rate with grain shape is derived, proving that the non-linear variation of Q has its origin in the non-linear variation of the packing fraction with grain shape measured at the centre of the orifice.
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Dates et versions

hal-04598530 , version 1 (03-06-2024)

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  • HAL Id : hal-04598530 , version 1

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Agathe Bignon, Emilien Azéma, Mathieu Renouf. Elongated Grains in Silos: A 3D Odyssey through Non-linear Flow Variations. EMMC19-19th European Mechanics of Materials Conference, May 2024, Madrid, Spain. ⟨hal-04598530⟩
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