Granular Fluids

Long-range Correlation in Sheared Granular Fluids

The time and the spatial correlations play important roles in non-equilibrium statistical physics [1-16]. The behaviors of the correlation functions in ordinary fluids are well understood. It is known that there exist long-time tails in the time correlation functions in fluids at equilibrium [1, 2, 3, 4]. In addition, long-range correlations exist in the spatial correlation functions in non-equ...

Long-time tails for sheared fluids

The long-time behaviors of the velocity autocorrelation function (VACF) for sheared fluids are investigated theoretically and numerically. It is found the existence of the cross-overs of VACF from t to t in sheared fluids of elastic particles without any thermostat, and from t to t in both sheared fluids of elastic particles with a thermostat and sheared granular fluids, where d is the spatial ...

Linear stability analysis of a vertically oscillated granular layer.

We present a linear stability analysis of an oscillating granular layer, treating it as an isothermal incompressible fluid with zero surface tension, which undergoes periodic collisions with and separations from an oscillating plate. Because the viscosity of the granular layer is unknown, we use the experimental value of the critical acceleration for the transition from a flat to patterned laye...

Hard sphere dynamics for normal and granular fluids.

A fluid of N smooth, hard spheres is considered as a model for normal (elastic collision) and granular (inelastic collision) fluids. The potential energy is discontinuous for hard spheres so that the pairwise forces are singular and the usual forms of Newtonian and Hamiltonian mechanics do not apply. Nevertheless, particle trajectories in the N particle phase space are well defined and the gene...

Reversible axial segregation of rotating granular media.

Density fluctuations in a model for vibrated granular media.

This paper presents the study of density fluctuations in a model for vibrated granular media. Their microscopic origin is shown to be linked to the microscopic disorder in grains packing. Varying vibrations amplitude and duration, several regimes are found for density relaxation. Its power spectrum is well described by power laws.