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Laser-Doppler measurements on a round turbulent jet in dilute polymer solutions

Barker, Steven J. (1973) Laser-Doppler measurements on a round turbulent jet in dilute polymer solutions. Journal of Fluid Mechanics, 60 (4). pp. 721-731. ISSN 0022-1120. doi:10.1017/S0022112073000431.

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A laser-Doppler velocimeter suitable for the measurement of mean and fluctuating flow velocities in water is described. Results of a study using this system in an axisymmetric turbulent jet of water and dilute polymer solutions are given. The laser-Doppler technique is better suited for such measurements than either Pitot tubes or heat-transfer gauges because the Doppler velocity measurements are independent of the physical properties of the fluid. Previous velocity measurements in polymer jets have suffered from the effects of the additives upon the sensors. Turbulent round jets with Reynolds numbers between 5000 and 50000 were studied. For a jet issuing from a convergent nozzle the additives were found to have no effect upon the mean axial velocity or turbulence intensity at any point in the jet. However, for a jet issuing from a long length of circular pipe, the additives reduced the centre-line velocity and increased the turbulence level in the early part of the jet. Thus the principal effect of a polymer additive upon the jet appears to result from its effect upon the initial conditions.

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Additional Information:© 1973 Cambridge University Press . Received 11 August 1972 and in revised form 11 April 1973. Published Online March 29 2006.
Issue or Number:4
Record Number:CaltechAUTHORS:20120719-135724262
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32594
Deposited By: Tony Diaz
Deposited On:19 Jul 2012 21:16
Last Modified:09 Nov 2021 21:28

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