Granular flow from a silo: Discrete-particle simulations in three dimensions

Molecular (or granular) dynamics methods are used to study the gravity-driv en flow of granular material through a horizontal aperture in three dimensi ons. The grains are spherical and modeled using a short-range repulsive int eraction, together with normal and tangential frictional damping forces. Th e material is contained in a rough-walled cylindrical container with a circ ular hole in its base, and to permit. flow measurements under steady-state conditions a continuous feed approach is employed in which exiting grains a re replaced at the upper surface of the material. The dependence of flow ve locity and discharge rate on aperture diameter is found to agree with exper iment; other quantities such as the kinetic energy and pressure distributio ns are also examined.