A mechanism of polymer induced drag reduction in turbulent pipe flow

dc.contributor.authorZadrazil, I.
dc.contributor.authorMarkides, Christos N.
dc.date.accessioned2015-04-23T09:08:56Z
dc.date.available2015-04-23T09:08:56Z
dc.date.issued2014
dc.description.abstractPaper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.en_ZA
dc.description.abstractPolymer induced drag reduction in turbulent pipe flow was investigated using a non-intrusive laser based diagnostic technique, namely Particle Image Velocimetry (PIV). The drag reduction was measured in a pressure-driven flow facility, in a horizontal pipe of inner diameter 25.3 mm at Reynolds numbers ranging from 35 000 to 210 000. Three high-molecular-weight polymers (polyethylene oxide 2×106 – 8×106 Da) at concentrations in the range of 5 – 250 wppm were used. The results, obtained from the PIV measurements, show that the drag reduction scales with the magnitude of the normalized streamwise and spanwise rms velocity fluctuations in the flow. This scaling seems to universal, and is independent of the Reynolds number and in some cases also independent of the distance from the wall where the velocity fluctuations are considered. Furthermore, the instantaneous PIV observations indicate that as the level of drag reduction increases, the flow in the pipe is separated into a low-momentum flow region near the pipe wall and a high-momentum flow region in the turbulent core. Based on these findings a new mechanism of polymeric drag reduction is proposed in this paper.en_ZA
dc.description.librariancf2015en_ZA
dc.format.mediumPDFen_ZA
dc.identifier.citationZadrazil, I, Markides, CN 2014, 'A mechanism of polymer induced drag reduction in turbulent pipe flow', Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.en_ZA
dc.identifier.isbn97817759206873
dc.identifier.urihttp://hdl.handle.net/2263/44533
dc.publisherInternational Conference on Heat Transfer, Fluid Mechanics and Thermodynamicsen_ZA
dc.rights© 2014 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.en_ZA
dc.subjectTurbulent pipe flowen_ZA
dc.subjectPolymer induced drag reductionen_ZA
dc.subjectParticle image velocimetryen_ZA
dc.subjectDrag reductionen_ZA
dc.subjectVelocity fluctuationsen_ZA
dc.subjectFlow regionsen_ZA
dc.titleA mechanism of polymer induced drag reduction in turbulent pipe flowen_ZA
dc.typePresentationen_ZA

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