Diffusion and Correlations in Lattice Gas Automata

Details Diffusion and Correlations in Lattice Gas Automata Diffusion and Correlations in Lattice Gas Automata

1997-11-13

arxiv.org/abs/cond-mat/9711123v1

Physical Review E (December 1997)

Physics

Condensed Matter

Statistical Mechanics

9 pages (revtex source), 12 Postscript figures

Scientific paper

10.1103/PhysRevE.56.6331

We present an analysis of diffusion in terms of the spontaneous density fluctuations in a non-thermal two-species fluid modeled by a lattice gas automaton. The power spectrum of the density correlation function is computed with statistical mechanical methods, analytically in the hydrodynamic limit, and numerically from a Boltzmann expression for shorter time and space scales. In particular we define an observable -- the weighted difference of the species densities -- whose fluctuation correlations yield the diffusive mode independently of the other modes so that the corresponding power spectrum provides a measure of diffusion dynamics solely. Automaton simulations are performed to obtain measurements of the spectral density over the complete range of wavelengths (from the microscopic scale to the macroscopic scale of the automaton universe). Comparison of the theoretical results with the numerical experiments data yields the following results: (i) the spectral functions of the lattice gas fluctuations are in accordance with those of a classical `non-thermal' fluid; (ii) the Landau-Placzek theory, obtained as the hydrodynamic limit of the Boltzmann theory, describes the spectra correctly in the long wavelength limit; (iii) at shorter wavelengths and at moderate densities the complete Boltzmann theory provides good agreement with the simulation data. These results offer convincing validation of lattice gas automata as a microscopic approach to diffusion phenomena in fluid systems.

Affiliated with

Also associated with

No associations

Rating

Diffusion and Correlations in Lattice Gas Automata does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Diffusion and Correlations in Lattice Gas Automata, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Diffusion and Correlations in Lattice Gas Automata will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-464052