A granular gas may be modeled as a set of hard-spheres undergoing inelastic collisions; its microscopic dynamics is thus strongly irreversible. As pointed out in several experimental works bearing on turbulent flows or granular materials, the power injected in a dissipative system to sustain a steady-state over an asymptotically large time window is a central observable. I will first present a phenomenological model able to describe the results of an experiment in which the steady state is achieved injecting energy trough the boundary (e.g. a vibrating wall). Then, I will describe an analytic approach allowing to determine the full distribution of the power injected in a model of randomly driven granular gas.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..