Shock propagation in locally driven granular systems

We study shock propagation in a system of initially stationary hard-spheres that is driven by a continuous injection of particles at the origin. The disturbance created by the injection of energy spreads radially outwards through collision between particles. Using scaling arguments, we determine the exponent characterizing the power law growth of this disturbance in all dimensions. The scaling functions describing the various physical quantities are determined using large scale event driven simulations in two and three dimensions for both the elastic and the inelastic system. The results are shown to describe well the data from two different experiments on granular systems that are similarly driven.