## Transport properties in granular gases. Inelastic particles and elastic particles with friction.

By: Antonio Astillero Vivas

From: CFTC and Universidade de Extremadura, Spain

At: Complexo Interdisciplinar, Anfiteatro

[2008-06-04]

The prototype model of a fluidized granular system is a gas of inelastic hard spheres (IHS) with a constant coefficient of normal restitution α. Using a kinetic theory description we investigate the two basic ingredients that a model of elastic hard spheres (EHS) must have in order to mimic the most relevant transport properties of the underlying IHS gas. First, the EHS gas is assumed to be subject to the action of an effective drag force with a friction constant equal to half the cooling rate of the IHS gas, the latter being evaluated in the local equilibrium approximation for simplicity. Second, the collision rate of the EHS gas is reduced by a factor (1 + α)/2, relative to that of the IHS gas. Also we test the above expectation in a paradigmatic non equilibrium state, namely, the simple or uniform shear flow (USF), by performing Monte Carlo computer simulations of the Boltzmann equation for both classes of dissipative gases, namely, IHS and EHS + friction.