Relaxation of granular gas under gravity

The granular gas dynamics under gravity is investigated by means of numerical simulation for the case of elastic collisions. Damped oscillations in the process of evolution to equilibrium are found and considered in detail. The nature of the oscillations is the deviation of the position of the centre-of-mass of the system from the equilibrium one when the particles’ initial velocity distribution is isotropic. The influence of several parameters on the oscillation frequency and the damping rate are determined.