Hydrodynamic properties of confined fluids

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Abstract
In the present work, we study the dynamical properties of fluids confined at molecular scales. First, we show that, for a fluid confined between two parallel solid walls, the phenomenological hydrodynamic description of bulk fluids holds down to nanoscopic scales, once appropriate boundary conditions at the solid walls are applied. Then, we investigate the influence of confinement on the self-diffusion coefficient (in the direction parallel to the walls) in a fluid slab. We have computed the effect of confinement on the mode-coupling contribution to the diffusion coefficient. These finite-size corrections are shown to reduce the diffusion constant by an amount , where h is the thickness of the fluid slab and the atomic size. This behaviour can be interpreted in terms of the suppression of long-wavelength modes in the backflow effect, due to confinement.