Laser Doppler diagnostics of vorticity and phenomenological description of the flows of dilute polymer solutions in model tubes

1991 ◽  
Author(s):  
E. V. Fedoseeva ◽  
Marina S. Polyakova
Keyword(s):  
Polymer Solutions ◽  
Laser Doppler ◽  
Phenomenological Description ◽  
Dilute Polymer Solutions

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

1973 ◽  
Vol 60 (4) ◽  
pp. 721-731 ◽  
Author(s):  
Steven J. Barker
Keyword(s):  
Polymer Solutions ◽  
Initial Conditions ◽  
Laser Doppler ◽  
Turbulent Jet ◽  
Laser Doppler Velocimeter ◽  
Doppler Velocity ◽  
Velocity Measurements ◽  
Convergent Nozzle ◽  
Round Jets ◽  
Dilute Polymer Solutions

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.

On the mechanism of drag reduction in dilute polymer solutions

1996 ◽  
Vol 55 (4) ◽  
pp. 289-295 ◽  
Author(s):  
K. Hoyer ◽  
A. Gyr ◽  
A. Tsinober
Keyword(s):  
Drag Reduction ◽  
Polymer Solutions ◽  
Dilute Polymer Solutions
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