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Article Dans Une Revue EPL - Europhysics Letters Année : 2002

Tracer diffusivity in a time or space dependent temperature field

Résumé

The conventional assumption that the self-diffusion coefficient of a small tracer can be obtained by a local and instantaneous application of Einstein\'s relation in a temperature field with spatial and temporal heterogeneity is revisited. It is shown that hydrodynamic fluctuations contribute to the self-diffusion tensor in a universal way, i.e. independent of the size and shape of the tracer. The hydrodynamic contribution is anisotropic--it reflects knowledge of the global anisotropy in the temperature profile, leading to anisotropic self-diffusion tensor for a spherical tracer. It is also retarded--it creates memory effects during the diffusion process due to hydrodynamic interactions.

Dates et versions

hal-00008765 , version 1 (14-09-2005)

Identifiants

Citer

Ramin Golestanian, Armand Ajdari. Tracer diffusivity in a time or space dependent temperature field. EPL - Europhysics Letters, 2002, 59, pp.800-806. ⟨10.1209/epl/i2002-00113-x⟩. ⟨hal-00008765⟩
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