Microstructure and Turbulence in Dilute Polymer Solutions
An appropriate picture of the interaction of polymers chains and turbulence structure is crucial to grasp the drag-reducing mechanisms of dilute polymers solutions. In most models the physically small diffusion is normally neglected. However, in the presence of a continuous spectrum of length and time scales, like in turbulence, the introduction of a diffusion term, however small, is crucial to enforce a cutoff at large wave number. Such a term can also be regarded as a natural consequence of a detailed picture of the substructural interactions between the polymeric chains and the fluid. The results obtained through numerical simulations are used in the appropriate thermodynamic framework to extract valuable information concerning the interaction between turbulence and microstructure. A general multifield formulation is finally employed to explore possible additional interaction mechanisms between neighboring populations of polymers that may play a role in accounting for slightly nonlocal interactions between polymer macromolecules in the solvent.
KeywordsProbability Density Function Material Element Deborah Number Extra Stress Nonlocal Interaction
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