Vibrated granular media as experimentally realizable granular gases

S. McNamara1, 3 and E. Falcon2
1 Centre Européen de Calcul Atomique et Moléculaire, 46 allée d'Italie, 69364 Lyon cedex 07, France
2 Laboratoire de Physique, École Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon cedex 07, France
3 current address: Institute for Computer Applications 1, Universität Stuttgart, 70569 Stuttgart, Germany 


in "Granular Gas Dynamics", Vol. 624 of Lectures Notes in Physics, T. Pöschel and  N. V. Brilliantov (Eds.), Springer-Verlag Heidelberg, Berlin, p. 347 - 366  (2003). 

ISSN: 1616-6361


We report numerical simulations of strongly vibrated granular materials designed to mimic recent experiments performed both in presence [1, 2, 3] or absence [4] of gravity.  We show that a model with impact velocity dependent restitution coefficient is necessary to bring the simulations into agreement with experiments. We measure the scaling exponents of the granular temperature, collision frequency, impulse and pressure with the vibrating piston velocity.

As the system changes from a homogeneous gas state at low density to a clustered state at high density, these exponents are all found to decrease continuously with the particle number. In absence of gravity, a loose cluster appears near the upper wall, opposite the piston, and acts as a buffer for fastest particles leading to unexpected non-extensive scaling exponents ; whereas in presence of gravity, the cluster bounces as a single inelastic body. All these results differ significantly from classical inelastic hard sphere kinetic theory and previous simulations, both based on a constant restitution coefficient.  

Full article: PDF file (452 KB) also in cond-mat/0311455 and ccsd-00000854


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