Steady uniform shear flow in a low density granular gas

The steady uniform shear flow of a low density granular sytem is studied by means of a kinetic model equation and also by direct Monte Carlo simulation of the Boltzmann equation. The former can be exactly solved for arbitrary shear rate and dissipation. Explicit expressions for the one-particle distribution function and the pressure tensor are obtained. Comparison of the results with those of previous theories is presented in the appropriate limits. The simulation shows that the model reproduces fairly well the values of the stresses and, in particular, the phenomenon of normal stress differences. The agreement is also very good for the velocity distribution function in the thermal velocity region, although significant discrepancies appear for large velocities.