Complex fluids exist in nature and are continually engineered for specific applications
involving the addition of macromolecules to a solvent, among other means. This imparts …

The dissolution of minute concentration of polymers in wall-bounded flows is well-known for
its unparalleled ability to reduce turbulent friction drag. Another phenomenon, elasto-inertial …

Viscoelastic fluids are a common subclass of rheologically complex materials that are
encountered in diverse fields from biology to polymer processing. Often the flows of …

A small amount of polymer additives can cause substantial reduction in the energy
dissipation and friction loss of turbulent flow. The problem of polymer-induced drag …

This article provides a review of recent progress in understanding and predicting polymer
drag reduction (DR) in turbulent wall-bounded shear flows. The reduction in turbulent friction …

The Oldroyd-B model has been used extensively to predict a host of instabilities in shearing
flows of viscoelastic fluids, often realized experimentally using polymer solutions. The …

Turbulent drag reduction by polymer additives in a channel is investigated using direct
numerical simulation. The dilute polymer solution is expressed with an Oldroyd-B model that …

It is well known that the drag in a turbulent flow of a polymer solution is significantly reduced
compared to Newtonian flow. Here we consider this phenomenon by means of a direct …

Drag reduction due to dilute addition of high polymers has been known for about fifty years.
In spite of this long history, many aspects of the problem remain poorly understood. Two of …

▪ Abstract Drag reduction in wall-bounded flows can be achieved by transverse motions
imposed by passive means, eg, riblets, or by external forcing, such as wall oscillation or …