Drag Reduction in Turbulent Flows by Polymer and Fiber Additives

This article provides a review of the recent progress in understanding and predicting additives-induced drag reduction (DR) turbulent wall-bounded shear flows. We focus on friction losses by dilute addition high-molecular weight polymers and/or fibers to flowing liquids. Although it has long been reasoned that dynamical interactions between polymers/fibers turbulence are responsible for DR, was not until recently made elucidating these detail. Advancements come largely from numerical simulations viscoelastic detailed measurements flows polymer/fiber solutions. Their impact current mechanics prediction DR is discussed, perspectives further advancement knowledge provided.