J. J. Brey 1, M. I. Garcia de Soria 2, P. Maynar 1, 3
Europhysics Letters (EPL) 84 (2008) 24002
A numerical molecular dynamics experiment measuring the two-time correlation function of the transversal velocity field in the homogeneous cooling state of a granular gas is reported. By measuring the decay rate and the amplitude of the correlations, the accuracy of the Landau-Langevin equation of fluctuating hydrodynamics is checked. The results indicate that although a Langevin approach can be valid, the fluctuation-dissipation relation must be modified, since the viscosity parameter appearing in it differs from the usual hydrodynamic shear viscosity.
- 1. Fisica Teorica, Universidad de Sevilla,
Universidad de Sevilla - 2. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
CNRS : UMR8626 – Université Paris XI – Paris Sud - 3. Laboratoire de Physique Théorique d’Orsay (LPT),
CNRS : UMR8627 – Université Paris XI – Paris Sud