Abstract
The behavior of dilute polymer solutions in strong periodic flows is studied. On time scales much greater than the flow period fluctuations in centre-of-gravity position are governed by an anisotropic and enhanced diffusivity matrix. We demonstrate that the size and density of a diffusing cloud grows and decays, respectively, more rapidly than without flow. At high frequencies the polymer chain size and monomer diffusivity are enhanced by the same "factor" as the centre-of-gravity in a Rouse dynamics treatment. Density fluctuations are anisotropic and on the average reduced by flow. All effects are non-linear in the strain amplitude of the flow.