Transient structures in a Granular Gas

A force-free granular gas is considered with impact-velocity dependent coefficient of restitution as it follows from the model of viscoelastic particles. We analyze structure formation in this system by means of three independent methods: Molecular Dynamics, numerical solution of the hydrodynamic equations and linear stability analysis of these equations. All these approaches indicate that structure formation occurs in force-free granular gases only as a transient process.