Drag Reduction in Turbulent Wall-Bounded Flows of Realistic Polymer Solutions
F. Serafini, F. Battista, P. Gualtieri, Carlo Massimo Casciola
Abstract
Suspensions of DNA macromolecules (0.8 wppm, 60 kbp), modeled as finitely extensible nonlinear elastic dumbbells coupled to the Newtonian fluid, show drag reduction up to 27% at friction Reynolds number 180, saturating at the previously unachieved Weissenberg number ≃10^{4}. At a large Weissenberg number, the drag reduction is entirely induced by the fully stretched polymers, as confirmed by the extensional viscosity field. The polymer extension is strongly non-Gaussian, in contrast to the assumptions of classical viscoelastic models.
Topics & Concepts
Weissenberg numberDragTurbulenceReynolds numberViscoelasticityNewtonian fluidReduction (mathematics)ViscosityPhysicsClassical mechanicsMechanicsExtensional viscosityBounded functionMaterials scienceThermodynamicsMathematical analysisMathematicsGeometryShear viscosityRheology and Fluid Dynamics StudiesFluid Dynamics and Turbulent FlowsGranular flow and fluidized beds