The dynamics of billiards with no-slip collisions

Abstract We propose a new model of a gas of rough hard spheres that includes inelastic effects. The spheres interact with each other and with the container walls through inelastic collisions. The impulsive friction without slipping at the impacts conserves the total energy of the system, but mixes the tangential velocity components with the angular velocities of coliding spheres. We explore the — sometimes surprising — consequences of this in a simple billiard model.