Discharge of granular matter by gravity

MARCOS A. MADRID; LUIS A. PUGNALONI

Mendoza

Simposio; VI Latin American Symposium on High Performance Computing HPCLatAm; 2013

In 1895 Janssen presented an analytic model for the bottom pressure in a cylindrical vessel filled with grains which explained the empirical observation that the pressure is independent of the height of the column. In 1961, Beverloo carried out experiments which indicated that the grain outflow through a hole in the bottom of a silo is independent of the height of the column. Since then, the constant pressure and constant outflow have been considered cause and effect. Recently, it has been shown that such relationship is not really valid; even if the bottom pressure remains constant, the flow rate may be changed. In the same direction, it has been demonstrated that the bottom pressure could change even if the flow rate remains constant. We aim at understanding the origin of the Beverloo's law based on more fundamental physical phenomena. To do so, we carry out discrete element simulations (DEM) of the discharge of a silo filled with spherical grains interacting through spring-dashpots in the normal and tangential direction of the contacts plus an implementation of the Coulomb criterion to switch between static and dynamic friction. We present preliminary results showing that simulations comply with the Beverloo's rule and show an initial performance analysis of the parallelization of the simulations using the software YADE.