Spontaneous wave pattern formation in vibrated granular materials

This paper presents two-dimensional particle dynamics simulations of a vertically vibrated layer of granules, wherein a spontaneous formation of parametric surface waves appears. The investigation of the dynamic process and mechanism that leads to the formation of the granular surface waves has revealed that the dissipation coefficient in shear direction plays a crucial role in the formation of wave patterns. Scaling relations between the units in simulations and experiments are evaluated. Simulation results are shown to compare well with experimental ones.