SIMULATIONS OF 2-DIMENSIONAL ARRAYS OF BEADS UNDER EXTERNAL VIBRATIONS - SCALING BEHAVIOR

We present a series of simulations on systems of beads enclosed in two -dimensional (2D) boxes, and compare the results of molecular dynamics (MD) and event-driven algorithms. The beads collide inelastically and are submitted to vibrations. We vary over a wide range the parameters : the amplitude and the frequency of the vibrations, the number of par ticles, and the inelasticity of the collisions. While the height of th e center of mass of the system scales with respect to the restitution coefficient epsilon, the number of beads N and the typical velocity of the bottom plate, the functional dependence differs from the findings in 1D systems. We find that the MD results depend strongly on the tim e t(c) during which the particles are in contact.