Modification of turbulent boundary layer coherent structures with drag reducing polymer solution

The modification of dominant coherent structures that extend through the log-region of a drag reduced turbulent boundary layer is studied via examination of two-point correlations from time-resolved particle-image-velocimetry. Measurements were acquired in polymer oceans (uniform concentration) at d...

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Bibliographic Details
Published inPhysics of fluids (1994) Vol. 32; no. 1
Main Authors Farsiani, Yasaman, Saeed, Zeeshan, Jayaraman, Balaji, Elbing, Brian R.
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 01.01.2020
Subjects
Coherence
Correlation analysis
Drag reduction
Fluid dynamics
Image acquisition
Inclination
Oceans
Physics
Pneumatics
Polymers
Turbulent boundary layer
Variation
Velocimetry
Velocity distribution
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Summary:The modification of dominant coherent structures that extend through the log-region of a drag reduced turbulent boundary layer is studied via examination of two-point correlations from time-resolved particle-image-velocimetry. Measurements were acquired in polymer oceans (uniform concentration) at drag reduction levels corresponding to the low drag reduction regime (<40%) and the high drag reduction (HDR) regime (>40%) and at an intermediate level (46%). The mean velocity profiles and two-point correlations were compared with those of water (Newtonian, DR = 0%). These results show that, with increasing drag reduction, the inclination of these dominant coherent structures decreases, their streamwise extent increases, and the fluctuations in the correlations are suppressed (especially at HDR). These observations are examined in comparison with the coherent structure literature (Newtonian and polymeric).
ISSN:1070-6631
1089-7666
DOI:10.1063/1.5127293