Heterogeneous drag reduction in turbulent pipe flows using various injection techniques

Frings, B.

doi:10.1007/bf01372455

Cited by 20 publications

(7 citation statements)

References 32 publications

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“…In a pipe-flow study comparing various injection techniques of polymer solutions into water, drag reductions of up to 80 per cent were achieved (Frings 1988). Additionally, the drag-reduction benefit increases with increased Reynolds number.…”

Section: (B) Effect Of Fish Mucus and Polymers On Fluid Dragmentioning

confidence: 99%

“…Similar to these fish-mucus experiments, polymer additives in pipe flows have been known for many years to reduce the drag in fluid flows by extreme amounts. In a pipe-flow study comparing various injection techniques of polymer solutions into water, drag reductions of up to 80 per cent were achieved (Frings 1988). Additionally, the drag-reduction benefit increases with increased Reynolds number.…”

Section: (A) the Effect Of Fluid-surface Bonding On Drag Reductionmentioning

confidence: 99%

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Shark-skin surfaces for fluid-drag reduction in turbulent flow: a review

Dean

Bhushan

2010

Phil. Trans. R. Soc. A.

623

381

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The skin of fast-swimming sharks exhibits riblet structures aligned in the direction of flow that are known to reduce skin friction drag in the turbulent-flow regime. Structures have been fabricated for study and application that replicate and improve upon the natural shape of the shark-skin riblets, providing a maximum drag reduction of nearly 10 per cent. Mechanisms of fluid drag in turbulent flow and riblet-drag reduction theories from experiment and simulation are discussed. A review of riblet-performance studies is given, and optimal riblet geometries are defined. A survey of studies experimenting with riblettopped shark-scale replicas is also given. A method for selecting optimal riblet dimensions based on fluid-flow characteristics is detailed, and current manufacturing techniques are outlined. Due to the presence of small amounts of mucus on the skin of a shark, it is expected that the localized application of hydrophobic materials will alter the flow field around the riblets in some way beneficial to the goals of increased drag reduction.

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Section: (B) Effect Of Fish Mucus and Polymers On Fluid Dragmentioning

confidence: 99%

Section: (A) the Effect Of Fluid-surface Bonding On Drag Reductionmentioning

confidence: 99%

Shark-skin surfaces for fluid-drag reduction in turbulent flow: a review

Dean

Bhushan

2010

Phil. Trans. R. Soc. A.

623

381

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“…Vleggaar & Tels 1973;Frings 1988;Hoyt & Sellin 1991;Sun Chee Fore, Szwalek & Sirviente 2005). Vleggaar & Tels (1973) and Frings (1988) reported that the heterogeneous drag reduction was significantly larger than that obtained for homogeneous polymer solutions of the same average concentration. Sun Chee Fore et al (2005) also reported that the polymer injection could be more or less cost-effective compared to the preparation of polymer solution, depending on the type of polymer.…”

mentioning

confidence: 94%

“…the streamwise variations of turbulent dynamics, however, the accumulation of experimental data, especially comparison of homogeneous and heterogeneous drag reduction, is required, while such a comparison of drag reduction between homogeneous and heterogeneous polymer solutions has been reported for turbulent pipe flows (e.g. Vleggaar & Tels 1973;Frings 1988;Hoyt & Sellin 1991;Sun Chee Fore, Szwalek & Sirviente 2005). Vleggaar & Tels (1973) and Frings (1988) reported that the heterogeneous drag reduction was significantly larger than that obtained for homogeneous polymer solutions of the same average concentration.…”

mentioning

confidence: 98%

Turbulent drag reduction of boundary layer flow with non-ionic surfactant injection

2014

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We experimentally investigated streamwise variations of turbulent dynamics in drag-reducing turbulent boundary layer flows following the injection of non-ionic surfactant solutions, which mainly consisted of oleyldimethylamine oxide. We focus on the comparison of turbulence statistics between injected (i.e. heterogeneous) and premixed (i.e. homogeneous) surfactant solutions, in which the maximum drag reduction ratio of 50 % is the same at the most downstream position for both cases. The wall-normal profiles of turbulence statistics, such as streamwise and wall-normal turbulence intensities, seem to be noticeably different between heterogeneous and homogeneous surfactant solutions. However, streamwise variations in these maxima and the wall-normal locations are essentially similar to one another, except for the maximum of streamwise turbulence intensity, which is not arranged by the amount of drag reduction and is also dependent on the normalization due to outer and inner variables. Such complex behaviour of streamwise turbulence intensity would be caused by the formation of near-wall layered structures that are parallel to the wall. For both heterogeneous and homogeneous surfactant solutions, the streamwise variation in the drag reduction ratio corresponds well to those of the mean velocity in wall units and the wall-normal locations of maxima of streamwise and wall-normal turbulence intensities with both outer and inner scaling. Unlike the Reynolds shear stress, the correlation coefficient of the streamwise and wall-normal turbulent fluctuations is correlated well with the drag reduction ratio. We present plausible pictures of the development of turbulence structures such as hairpin vortices and low-speed streaks for the drag-reducing turbulent boundary layer in heterogeneous and homogeneous surfactant solutions, which are comprehensively derived from the present set of experimental measurements such as flow visualization, planar laser-induced fluorescence, two-component laser-Doppler velocimetry and particle image velocimetry on the streamwise and wall-normal plane and the streamwise and spanwise plane.

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“…To improve drag reduction performance, a drag reduction agent was intensively investigated recently as an alternative of drag reduction riblet, taking fish epidermal mucus as inspiration. Fringes et al 8 conducted an experimental study of the impact of injecting concentrated polymer solutions into the near-wall region of a turbulent pipe flow and achieved 80% maximum drag reduction. Mizunuma et al [9][10][11][12] tested the synergistic effects of turbulent drag reduction by pouring a great quantity of polymer additive directly into fluid.…”

Section: Introductionmentioning

confidence: 99%

UV grafting process for synthetic drag reduction of biomimetic riblet surfaces

Chen

Che

Zhang

et al. 2015

J of Applied Polymer Sci

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Skin–friction drag accounts for a large portion of resistance encountered by water‐based vehicles, such as ships and submarines. Developing drag reduction methods to improve drag reduction performance has drawn worldwide attention recently. UV‐induced polymerization has been investigated as a way to graft the drag reduction agent PAM on to a PVC substrate with a biomimetic riblet surface. The effects of AM concentration and irradiation time on the grafting rate were explored to determine optimal grafting parameters. UV grafting polymerization was clarified by comparing the peak absorption variation of the infrared spectrum before and after grafting. The PAM thin film grafted on riblet surface was measured approximately 10 µm in thickness. A rotating disk apparatus was built to measure the synthetic drag reduction performance. The drag reduction rate of the grafted PAM riblet surface was tested at approximately 14%, higher than the 6% of the traditional riblet surface. Moreover, the excellent drag reduction performance of grafted PDMS riblet surface lasted for 12 days. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42303.

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Heterogeneous drag reduction in turbulent pipe flows using various injection techniques

Cited by 20 publications

References 32 publications

Shark-skin surfaces for fluid-drag reduction in turbulent flow: a review

Shark-skin surfaces for fluid-drag reduction in turbulent flow: a review

Turbulent drag reduction of boundary layer flow with non-ionic surfactant injection

UV grafting process for synthetic drag reduction of biomimetic riblet surfaces

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