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Article Dans Une Revue Physical Review Fluids Année : 2020

Length of standing jumps along granular flows down smooth inclines

Résumé

Granular jumps-the change in height and depth-averaged velocity during granular flows-occur during transitions from thin and fast flows (supercritical) to thick and slow flows (subcritical). The present paper describes discrete element method simulations inspired by recent laboratory experiments, which produce standing jumps in two-dimensional free-surface dry granular flows down a slope. Special attention is paid to characterizing and measuring the finite length of those standing granular jumps, as well as to deciphering their internal structure. By varying macroscopic quantities, such as slope angle and mass discharge, and microscopic properties, such as interparticle friction and grain diameter, a rich variety of granular jump patterns is observed. Hydraulic-like granular jumps with an internal waterlike roller are identified, in addition to diffuse laminar granular jumps and steep colliding granular jumps. Moreover, a recently established depth-averaged relation for the prediction of jump heights is fed with the measured jump length and fitted against the numerical simulations to examine the effective friction in the granular medium for each type of jump. The dominant component of the general friction law is found to be different when transitioning from one jump pattern to the others. This study demonstrates that the granular jump pattern, and particularly its geometry and internal structure, can offer a stringent test for addressing the dissipation mechanisms that govern the flowability of granular media.
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Dates et versions

hal-02959890 , version 1 (07-10-2020)

Identifiants

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Ségolène Méjean, François Guillard, Thierry Faug, Itai Einav. Length of standing jumps along granular flows down smooth inclines. Physical Review Fluids, 2020, 5 (3), ⟨10.1103/PhysRevFluids.5.034303⟩. ⟨hal-02959890⟩
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