Inelastic Takahashi hard-rod gas

Abstract

We study a one-dimensional fluid of hard rods interacting with each other via binary inelastic collisions and a short-ranged square-well potential. Upon tuning the depth and the sign of the well, we investigate the interplay between dissipation and cohesive or repulsive forces. Molecular-dynamics simulations of the cooling regime indicate that the presence of this simple interparticle interaction is sufficient to significantly modify the energy dissipation rates expected by Haff's law for the free cooling. The simplicity of the model makes it amenable to an analytical approach based on the Boltzmann-Enskog transport equation which allows deriving the behavior of the granular temperature. Furthermore, in the elastic limit, the model can be solved exactly to provide a full thermodynamic description. A meaningful theoretical approximation explaining the properties of the inelastic system in interaction with a thermal bath can be directly extrapolated from the properties of the corresponding elastic system, upon a proper redefinition of the relevant observables. Simulation results both in the cooling and driven regimes can be fairly interpreted according to our theoretical approach and compare rather well to our predictions.