Hydrodynamics of granular particles on a line

We investigate a lattice model representing a granular gas in a thin channel. We deduce the hydrodynamicdescription for the model from the microscopic dynamics in the large-system limit, including the lowest finite-sizecorrections. The main prediction from hydrodynamics, when finite-size corrections are neglected, is the existenceof a steady "uniform longitudinal flow" (ULF), with the granular temperature and the velocity gradient bothuniform and directly related. Extensive numerical simulations of the system show that such a state can be observedin the bulk of a finite-size system by attaching two thermostats with the same temperature at its boundaries. Therelation between the ULF state and the shocks appearing in the late stage of a cooling gas of inelastic hard rodsis discussed.