title: Evolution of pressure profiles during the discharge of a silo.
abstract: We report measurements of the pressure profile in the outlet plane of a discharging silo. We observe that, whatever the preparation of the granular system, a dynamic Janssen effect is at play: the apparent mass of the grains (i.e., the part of their mass sustained by the base) is significantly smaller than their actual mass because of the redirection of the weight to the lateral wall of the container. The pressure profiles reveal a significant decrease in pressure in the vicinity of the outlet as the system discharges, whereas the flow rate remains constant. The measurements are thus a direct experimental proof that the flow rates of granular material through an aperture are not controlled by the local stress conditions.
authors.affiliation: Université de Lyon, Laboratoire de Physique, Ecole Normale Supérieure de Lyon, CNRS, 46 Allée d'Italie, F-69364 Lyon cedex 07, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Perge
authors.forename: María Alejandra
authors.initials: MA
authors.lastname: Aguirre
authors.forename: Paula Alejandra
authors.initials: PA
authors.lastname: Gago
authors.forename: Luis A
authors.initials: LA
authors.lastname: Pugnaloni
authors.forename: Denis
authors.initials: D
authors.lastname: Le Tourneau
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Géminard
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D002523:Edible Grain / Q000737:chemistry* / Q000648:ultrastructure*; D008956:Models, Chemical; D008958:Models, Molecular; D011312:Pressure
chemical_list: D003102:Colloids