Granular materials, like sand or powders, have many peculiar properties, most of them not yet fully understood. These are due to the special physical properties of granular media like dissipation, friction, dilatancy and the possibilities of having grains of many different sizes and shapes. In...

We present models to describe the dynamics of the surface of a dry granular bed, like a desert. These models, based on coupled differential equations can describe the formation and evolution of dunes. Field measurements have been performed to compare the numerical results. The concept of the...

We present a simple one-dimensional model to describe the evolution of a transverse dune field. The model is characterized by the distances between the dunes and their heights, which determine the inter-dune sand flux. The model reproduces the observation that the dunes in a given field have...

Formation dynamics of transient spiral and target patterns are studied for vertically oscillated thin granular layer systems. When the dimensionless acceleration amplitude is changed from 2.5 of a flat pattern state to 3.0 of a steady stripe pattern state by linearly ramping the oscillation...

We present experimental and theoretical studies of the shape of heaps. In the simplest case one has a cone with an angle of repose. A simple 1d model is presented and solved analytically to obtain this angle from the properties of individual grains. This model is generalized to take into account...

The splash and spill effects caused by the impact of a ball dropped from a height into a granular medium held in a small open container are examined. Different granular media, namely rice, mustard seeds, cream of wheat and plastic beads are used. The quantity of spilled-over granular matter (W,...

A stochastic lattice model for the simulation of sandpiles is presented. The model allows for the numerical investigation of the phase segregation phenomenon occurring when different granular species are initially mixed together before deposition. The model includes the collective motion of...

Using a simplified model of a dissipative discrete-particle fluid we study the formation of surface waves under vertical vibration. The only dissipative forces included in this two-dimensional molecular dynamics simulation act normally to the line of contact during collisions; transverse...

During experiments carried out several years ago to grow dendritic crystals while they are levitated in a tube containing rotating supersaturated solution, a curious banding process was observed, in which the crystals were seen to accumulate preferentially in periodic positions within the tube....

This work is a study on the formation of piles of granular materials using the particle dynamics method. Different models of tangential forces were examined for the analysis of stability of the pyramid of two-dimensional grains. The critical value of the coefficient of friction between grains at...