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Ecoulements gravitaires de materiaux granulaires

Abstract : This dissertation reports experimental and numerical results on dense, dry granular flows in an inclined channel. We describe the molecular dynamics method for soft spheres as well as the particle tracking and gamma-densitometry techniques. Experimental results on 2D flows are then presented. We focus on crystal ordering of a monodisperse medium within the flow, the velocity and packing fraction profiles and the structure of a propagating front of grains. Numerical and experimental results on super stable heaps are presented and the crucial role played by side-wall friction is pointed out. The growth of such a heap is also studied which gives insights into the erosion and accretion phenomena. Velocity, packing fraction and rotation speed profiles are investigated through numerical simulations. The major influence of side-wall friction on the properties of the flow is confirmed by the simulations. Finally, we study a regime in which a dense plug flow rides atop a basal, sheared, dilute and agitated layer. It is shown that the basal layer does not lead to any lubrication of the flow and that it does not seem to explain the mobility of the so-called long-runout avalanches. The low values of the apparent friction coe fficient of voluminous landslides can be numerically reproduced through simulations of dry and dense granular flows.
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https://tel.archives-ouvertes.fr/tel-00010108
Contributor : Nicolas Taberlet <>
Submitted on : Monday, September 12, 2005 - 12:16:21 PM
Last modification on : Tuesday, January 12, 2021 - 4:38:43 PM
Long-term archiving on: : Friday, April 2, 2010 - 9:52:13 PM

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  • HAL Id : tel-00010108, version 1

Citation

Nicolas Taberlet. Ecoulements gravitaires de materiaux granulaires. Physique [physics]. Université Rennes 1, 2005. Français. ⟨tel-00010108⟩

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