Imperial College London


Faculty of EngineeringDepartment of Chemical Engineering

Professor of Clean Energy Technologies



+44 (0)20 7594 1601c.markides Website




404ACE ExtensionSouth Kensington Campus






BibTex format

author = {Zadrazil, I and Markides, CN},
title = {A Mechanism of Polymer Induced Drag Reduction in Turbulent Pipe},
url = {},

RIS format (EndNote, RefMan)

AB - Polymer induced drag reduction in turbulent pipe flow wasinvestigated using a non-intrusive laser based diagnostictechnique, namely Particle Image Velocimetry (PIV). The dragreduction was measured in a pressure-driven flow facility, in ahorizontal pipe of inner diameter 25.3 mm at Reynoldsnumbers ranging from 35 000 to 210 000. Three high-molecular-weight polymers (polyethylene oxide 2x10^6 –8x10^6 Da) at concentrations in the range of 5 – 250 wppm wereused. The results, obtained from the PIV measurements, showthat the drag reduction scales with the magnitude of thenormalized streamwise and spanwise rms velocity fluctuationsin the flow. This scaling seems to universal, and is independentof the Reynolds number and in some cases also independent ofthe distance from the wall where the velocity fluctuations areconsidered. Furthermore, the instantaneous PIV observationsindicate that as the level of drag reduction increases, the flow inthe pipe is separated into a low-momentum flow region near thepipe wall and a high-momentum flow region in the turbulentcore. Based on these findings a new mechanism of polymericdrag reduction is proposed in this paper.
AU - Zadrazil,I
AU - Markides,CN
TI - A Mechanism of Polymer Induced Drag Reduction in Turbulent Pipe
UR -
ER -