title: Origin of density clustering in a freely evolving granular gas.
abstract: The physical mechanisms leading to the development of density inhomogeneities in a freely evolving low density granular gas are investigated. By means of the direct simulation Monte Carlo method, numerical solutions of the inelastic Boltzmann equation are constructed for both a perturbed system and also for an initially homogeneous state. Analysis of the Fourier components of the fields indicates that the nonlinear coupling contributions of the transversal velocity play a crucial role in the initial setup of clustering. A simple hydrodynamic model is proposed to describe what is observed in the simulations. Finally, the nature of the inhomogeneous state is briefly discussed.
authors.affiliation: Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, E-41080 Sevilla, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Brey
authors.forename: M J
authors.initials: MJ
authors.lastname: Ruiz-Montero
authors.forename: D
authors.initials: D
authors.lastname: Cubero