Evolution of pressure profiles during the discharge of a silo

Christophe Perge (1) , Maria Alejandra Aguirre (2) , Paula Alejandra Gago (3) , Luis A. Pugnaloni (3) , Denis Le Tourneau (1) , Jean-Christophe Géminard (1)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon
2 GMP - Grupo de Medios Porosos [Buenos Aires]
3 IFLYISB - Instituto de Física de Líquidos y Sistemas Biológicos

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 of the 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.

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Christophe Perge, Maria Alejandra Aguirre, Paula Alejandra Gago, Luis A. Pugnaloni, Denis Le Tourneau, et al.. Evolution of pressure profiles during the discharge of a silo. 2012. ⟨hal-00662418⟩