Lyapunov instability of rough hard-disk fluids

Author(s)
Jacobus A. van Meel, Harald Posch
Abstract

The dynamical instability of rough hard-disk fluids in two dimensions is characterized through the Lyapunov spectrum and the Kolmogorov-Sinai entropy hKS for a wide range of densities and moments of inertia I. For small I the spectrum separates into translation-dominated and rotation-dominated parts. With increasing I the rotation-dominated part is gradually filled in at the expense of translation until such a separation becomes meaningless. At any density, the rate of phase-space mixing, given by hKS, becomes less and less effective the more the rotation affects the dynamics. However, the degree of dynamical chaos, measured by the maximum Lyapunov exponent, is only enhanced by the rotational degrees of freedom for high-density gases but is diminished for lower densities. Surprisingly, no traces of Lyapunov modes were found in the spectrum for larger moments of inertia. The spatial localization of the perturbation vector associated with the maximum exponent however persists for any I.

Organisation(s)
Computational and Soft Matter Physics
External organisation(s)
University of Amsterdam (UvA)
Journal
Physical Review E
Volume
80
ISSN
1539-3755
DOI
https://doi.org/10.1103/PhysRevE.80.016206
Publication date
2009
Peer reviewed
Yes
Austrian Fields of Science 2012
1030 Physics, Astronomy
Portal url
https://ucrisportal.univie.ac.at/en/publications/b2eb4366-d28c-4828-9160-b482143f696c