11 research outputs found
Velocity Fluctuations in Electrostatically Driven Granular Media
We study experimentally the particle velocity fluctuations in an
electrostatically driven dilute granular gas. The experimentally obtained
velocity distribution functions have strong deviations from Maxwellian form in
a wide range of parameters. We have found that the tails of the distribution
functions are consistent with a stretched exponential law with typical
exponents of the order 3/2. Molecular dynamic simulations shows qualitative
agreement with experimental data. Our results suggest that this non-Gaussian
behavior is typical for most inelastic gases with both short and long range
interactions.Comment: 4 pages, 4 figure
Navier-Stokes transport coefficients of -dimensional granular binary mixtures at low density
The Navier-Stokes transport coefficients for binary mixtures of smooth
inelastic hard disks or spheres under gravity are determined from the Boltzmann
kinetic theory by application of the Chapman-Enskog method for states near the
local homogeneous cooling state. It is shown that the Navier-Stokes transport
coefficients are not affected by the presence of gravity. As in the elastic
case, the transport coefficients of the mixture verify a set of coupled linear
integral equations that are approximately solved by using the leading terms in
a Sonine polynomial expansion. The results reported here extend previous
calculations [V. Garz\'o and J. W. Dufty, Phys. Fluids {\bf 14}, 1476 (2002)]
to an arbitrary number of dimensions. To check the accuracy of the
Chapman-Enskog results, the inelastic Boltzmann equation is also numerically
solved by means of the direct simulation Monte Carlo method to evaluate the
diffusion and shear viscosity coefficients for hard disks. The comparison shows
a good agreement over a wide range of values of the coefficients of restitution
and the parameters of the mixture (masses and sizes).Comment: 6 figures, to be published in J. Stat. Phy