Dynamics of inelastically colliding spheres with Coulomb friction: Relaxation of translational and rotational energy

摘要

We investigate the free cooling of inelastic rough spheres in the presence of Coulomb friction. De- pending on the coefficients of normal restitution and Coulomb friction μ, we find qualitatively different as- Ymptotic states. For nearly complete normal restitution (close to 1) and large μ, friction does not change the cooling properties qualitatively compared to a con- stant coefficient of tangential restitution. In particular, the asymptotic state is characterized by a constant ratio of ro- tational and translational energies, both decaying accord- ing to Haff's law.