Self-diffusion in strongly driven flows: A non-equilibrium molecular dynamics study

The self-diffusion of simple liquids is studied in the presence of strong shear-free flow fields. At the state point of the system the shape of the velocity autocorrelation function is markedly different in the extension or contraction directions of elongation flow. Despite this pronounced directional dependence of the autocorrelation functions, the diagonal elements of the diffusion tensor are more uniform than in the case of planar Couette flow.