Modeling nonspherical particles using multisphere discrete elements

In this paper axisymmetrical particles are modeled as multisphere discrete elements using a method in which particles are represented by overlapping s pheres, fixed rigidly with respect to a local coordinate system. Contact de tection is sphere-based and the resultant forces are transformed to the par ticle centroid to calculate the particle motion using standard discrete ele ment method conventions. The multisphere method was used to model discharge of ellipse-shaped particles through an orifice in a flat-bottomed hopper a nd the simulations compared with physical experiments at the same scale. Th ere was good agreement between the flow behavior of the simulated and physi cal particle assemblies for all orifice sizes. The rate of discharge and th e vertical velocity profiles in the region of converging flow determined fo r the simulated and physical flows were in close agreement for flow from th e larger orifices. A similar relationship between frequency of arch formati on, particle mean diameter, and orifice diameter as for spheres was observe d.