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Diffusive Transport Enhanced By Thermal Velocity Fluctuations, Alejandro Garcia, Aleksandar Donev, Anton De La Fuente, John B. Bell

Alejandro Garcia

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. We find good agreement between a simple fluctuating hydrodynamics theory and particle and finite-volume simulations. The enhancement of the diffusive transport depends on the system size L and grows as ln⁡(L/L0) in quasi-two-dimensional systems, while in three dimensions it scales as L0-1-L-1, where L0 is a reference length. Our results demonstrate that fluctuations play an important role in the hydrodynamics of small-scale systems.