Marini-Bettolo-Marconi Umberto, Natali Maurizio, Costantini Giulio, Cecconi Fabio
Dipartimento di Fisica, Università di Camerino, Via Madonna delle Carceri, I-62032 Camerino, Italy.
J Chem Phys. 2006 Jan 28;124(4):044507. doi: 10.1063/1.2161215.
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.
我们研究了一种一维硬棒流体,它们通过二元非弹性碰撞以及短程方阱势相互作用。通过调整阱的深度和符号,我们研究了耗散与内聚或排斥力之间的相互作用。冷却状态的分子动力学模拟表明,这种简单的粒子间相互作用的存在足以显著改变哈夫定律所预期的自由冷却能量耗散率。该模型的简单性使其适用于基于玻尔兹曼 - 恩斯科格输运方程的解析方法,该方法可以推导颗粒温度的行为。此外,在弹性极限下,该模型可以精确求解以提供完整的热力学描述。在适当重新定义相关可观测量后,可以直接从相应弹性系统的性质推断出一个有意义的理论近似,用于解释与热浴相互作用的非弹性系统的性质。根据我们的理论方法,可以很好地解释冷却和驱动状态下的模拟结果,并且与我们的预测相当吻合。