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Article Dans Une Revue Physica A: Statistical Mechanics and its Applications Année : 2003

Temperature inversion in granular fluids under gravity

Résumé

We study, via hydrodynamic equations, the granular temperature profile of a granular fluid under gravity and subjected to energy injection from a base. It is found that there exists a turn-up in the granular temperature and that, far from the base, it increases linearly with height. We show that this phenomenon, observed previously in experiments and computer simulations, is a direct consequence of the heat flux law, different form Fourier's, in granular fluids. The positive granular temperature gradient is proportional to gravity and a transport coefficient $\mu_0$, relating the heat flux to the density gradients, that is characteristic of granular systems. Our results provide a method to compute the value $\mu_0$ for different restitution coefficients. The theoretical predictions are verified by means of molecular dynamics simulations, and the value of $\mu_0$ is computed for the two dimensional inelastic hard sphere model. We provide, also, a boundary condition for the temperature field that is consistent with the modified Fourier's law.

Dates et versions

hal-00122123 , version 1 (27-12-2006)

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Rosa Ramirez, Rodrigo Soto. Temperature inversion in granular fluids under gravity. Physica A: Statistical Mechanics and its Applications, 2003, 322, pp.73. ⟨hal-00122123⟩
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