Simulations of granular materials on different scales

Granular materials have very special properties as well in the solid state (packing) as in the fluidized state (e.g., under vibrations). To describe and predict their behaviour, computer simulation methods have been developed on different scales. Collision models take into account individual particle contacts and although once over 10(9) particles have been simulated for several microseconds in real time, these methods typically cannot treat more than 10(4) particles. On intermediate scales stochastic models and lattice models have been introduced in which details of the collisions are lost but particle numbers are high. (C) 2000 Elsevier Science B.V. All rights reserved.