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...

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...