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Accueil > Équipes > Equipe MEIGE : Modélisation, Expériences et Instrumentation pour la Géophysique et l’Environnement > Diffusion scientifique > Séminaires internes

Investigation of the mobile granular layer in bed-load transport

Julien Chauchat 19/01/2012

During this seminar I will present the results of of a join experimental, theoretical and numerical investigation of the bed-load layer in laminar shearing flow conditions. For this purpose we have set-up an indexed-matched experiment and we use PIV technique to measure the velocity profiles of the particles and the fluid. Based on the two-phase flow formalism we develop analytical and numerical solutions for this problem. The proposed two-phase model is based on the assumption of a Newtonian rheology for the fluid phase and a frictional one for the particulate phase (Coulomb or mu(I)). The fluid-particle interactions are restricted to Darcy drag and buoyancy leading to an hydrostatic pressure distribution for both phases at steady state. Our results shows that a frictional approach for the granular stresses in the moving layer allows to better understand bed-load transport in laminar flow conditions. The three-dimensional numerical simulations clearly show the geometrical effects induced by the lateral friction at the wall in this configuration and confirms the crucial role of side walls previously observed in dry granular flows.