2014/09/30 by Rodrigo Soto, Dino Risso, Ricardo Brito · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Boltzmann equation #Classical mechanics #Coefficient of restitution #Collision #Dissipation #Distribution function #Granular flow and fluidized beds #Kinetic energy #Kinetic theory #Material Dynamics and Properties #Materials science #Mechanics #Particle Dynamics in Fluid Flows #Physics #Quantum mechanics #Range (aeronautics) #Shear rate #Stationary state #Statistical physics #Thermodynamics #Viscosity #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.90.062204
9 pages, 4 figure; Accepted in Phys. Rev. E
arxiv created 2014/12/06 · openalex publication_date 2014/12/18 · arxiv updated 2015/06/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The shear viscosity in the dilute regime of a model for confined granular matter is studied by simulations and kinetic theory. The model consists on projecting into two dimensions the motion of vibrofluidized granular matter in shallow boxes by modifying the collision rule: besides the restitution coefficient that accounts for the energy dissipation, there is a separation velocity that is added in each collision in the normal direction. The two mechanisms balance on average, producing stationary homogeneous states. Molecular dynamics simulations show that in the steady state the distribution function departs from a Maxwellian, with cumulants that remain small in the whole range of inelasticities. The shear viscosity normalized with stationary temperature presents a clear dependence with the inelasticity, taking smaller values compared to the elastic case. A Boltzmann-like equation is built and analyzed using linear response theory. It is found that the predictions show an excellent agreement with the simulations when the correct stationary distribution is used but a Maxwellian approximation fails in predicting the inelasticity dependence of the viscosity. These results confirm that transport coefficients depend strongly on the mechanisms that drive them to stationary states.