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Reduction of skin friction by microbubbles and its relation with near-wall bubble concentration in a channel

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Abstract

Determination of the flow structure near the wall is essential for a clear insight into the phenomenon of skin friction reduction by microbubbles in a turbulent boundary layer. An important parameter, is the bubble concentration or void fraction in the wall region in drag-reducing conditions. The purpose of this paper is to show drag-reducing effects due to microbubbles in a water channel and, more importantly, to show the dependence of the drag-reduction values on the near-wall void fraction. A two-dimensional channel with an aspect ratio of 10 was specially built for this purpose with provisions for air injection through porous plates. Skin friction was directly measured by a miniature floating element transducer with a 5-mm circular sensing disk mounted flush on the top wall 67 channel-heights downstream of the injector. The wall friction in the presence of air bubbles was found to be reduced under the same bulk velocity when compared with the value without air. Detailed void fraction profiles across the channel were obtained by a sampling probe and a fiber-optic probe. Better collapse of the drag reduction data, independent of different profile shapes, was found when plotted against the near-wall void fraction than against a cross-sectional mean void fraction. While this dependence reconfirms that the phenomena are essentially inner-region dependent, the lack of influence of the bubble distribution patterns away from the wall implies lack of outer region influence.

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Abbreviations

b :

span of channel (m)

C f :

wall friction coefficient with air (=τw/0.5ρU 2m )

C f0 :

wall friction coefficient without air (=τw/0.5ρU 2m0 )

C v :

volumetric fraction of air in the boundary layer used in reference 5

DR :

percentage drag reduction (%)

f :

force experienced by the floating element (N)

h :

channel height (m)

k τ :

shear correction factor

L :

span-wise extent of bubbly region used in definingC v (m)

Q a :

volumetric injection rate of air (m3/s)

q a :

normalized injection velocity used in reference 4

Re 0 :

Reynolds number based onh and water properties, (=U 0 h/v)

S :

surface area of injector (m2)

U 0 :

center-line velocity (m/s)

U m :

effective bulk velocity with air (=Q a/bh+Um0) (m/s)

U m0 :

bulk velocity of water (m/s)

U ∞ :

free-stream velocity in boundary layer (m/s)

u τ :

friction velocity (\( = \sqrt {\tau _w /\rho } \)) (m/s)

u + :

velocity normalized byu τ

y :

wall normal distance (m)

y + :

coordinate in inner variables (=yu τ/v)

α:

void fraction

δ:

boundary-layer thickness (m)

δ* :

displacement thickness (m)

ρ:

kinematic viscosity of water (m2/s)

τw :

wall shear stress with air (N/m2)

τw0 :

wall shear stress without air (N/m2)

References

  1. McCormick ME, Bhattacharyya R (1973) Drag reduction of a submersible hull by electrolysis. Nav Eng J 85:11–16

    Article  Google Scholar 

  2. Bogdevich VG, Evseev AR, Malyuga AG et al (1977) Gassaturation effect on near-wall turbulence characteristics. Second International Conference on Drag Reduction, Cambridge, England, BHRA, pp 25–37

  3. Merkle CL, Deutsch S (1989) Microbubble drag reduction. In: Gad-el-Hak M (ed) Frontiers in experimental fluid mechanics, vol 46, Springer, Berlin, pp 291–335

    Google Scholar 

  4. Madavan NK, Deutsch S, Merkle CL (1984) Reduction of turbulent skin friction by microbubbles. Phys Fluids 27:356–363

    Article  Google Scholar 

  5. Madavan NK, Deutsch S, Merkle CL (1985) Measurements of local skin friction in a microbubble-modified turbulent boundary layer. J Fluid Mech 156:237–256

    Article  Google Scholar 

  6. Madavan NK, Deutsch S, Merkle CL (1985) Numerical investigation into the mechanisms of microbubble drag reduction. J Fluids Eng 107:370–377

    Article  Google Scholar 

  7. Merkle CL, Deutsch S, Pal S et al (1986) Microbubble drag reduction. Proceedings of the Sixteenth Symposium on Naval Hydrodynamics, Berkeley, California, USA, pp 199–215

  8. Pal S, Merkle CL, Deutsch S (1988) Bubble characteristics and trajectories in a microbubble boundary layer. Phys Fluids 31:744–751

    Article  Google Scholar 

  9. Pal S, Deutsch S, Merkle CL (1989) A comparison of shear stress fluctuation statistics between microbubble modified and polymer modified turbulent boundary layers. Phys Fluids A1:1360–1362

    Article  Google Scholar 

  10. Deutsch S, Castano J (1986) Microbubble skin friction reduction on an axisymmetric body. Phys Fluids 29:3590–3597

    Article  Google Scholar 

  11. Deutsch S, Pal S (1990) Local shear stress measurement on an axisymmetric body in a microbubble modified flow field. Phys Fluids A2:2140–2146

    Article  Google Scholar 

  12. Clark H III, Deutsch S (1991) Microbubble skin friction reduction on an axisymmetric body under the influence of applied axial pressure gradients. Phys Fluids A3:2948–2954

    Article  Google Scholar 

  13. Tokunaga K (1986) Reduction of frictional resistance of a flat plate by microbubbles. Trans West-Japan Society of Naval Architects 73, Berkeley, pp 79–82

  14. Baba E (1986) Discussion on Merkle et al.7 16th Symposium on Naval Hydrodynamics, Berkeley, California, USA, pp 214–215

  15. Kato H, Miyanaga M, Haramoto Y et al (1994) Frictional drag reduction by injecting bubbly water into a turbulent boundary layer. In: O'Hern TJ, Kim JH, Morgan WB et al (eds) Cavitation and gas-liquid flow in fluid machinery and devices. FED vol 190. ASME, New York, pp 185–194

    Google Scholar 

  16. Kato H, Miyanaga M, Yamaguchi H et al (1995) Frictional drag reduction by injecting bubbly water into a turbulent boundary layer and the effect of plate orientation. In: Serizawa A, Fukano T, Bataille J (eds) Advances in multiphase flow. Proceedings of the Second International Conference on Multiphase Flow. Kyoto, Japan, Elsevier, Amsterdam, pp 85–96

    Google Scholar 

  17. Guin MM (1995) Studies on frictional drag reduction by microbubbles in turbulent boundary layers. PhD thesis, The University of Tokyo, Japan

    Google Scholar 

  18. Hussain AKMF, Reynolds WC (1975) Measurements in fully developed turbulent channel flow. J Fluids Eng 97:568–580

    Google Scholar 

  19. Lumley JL (1977) Drag reduction in two phase and polymer flows. Phys Fluids 20 (Part II):S64-S71

    Article  Google Scholar 

  20. Marié JL (1987) A simple analytical formulation for microbubble drag reduction. Phys-Chem Hydrodyn 8:213–220

    Google Scholar 

  21. Kato H, Fujii Y, Yamaguchi H et al (1993) Frictional drag reduction by injecting high-viscosity fluid into turbulent boundary layer. J Fluids Eng 115:206–212

    Article  Google Scholar 

  22. Chanson H (1994) Drag reduction in open channel flow by aeration and suspended load. J Hyd Res 32:87–101

    Article  Google Scholar 

  23. Usui H (1989) Drag reduction caused by the injection of a polymer solution into a pipe flow. In: Gyr A (ed) Structure of turbulence and drag reduction. IUTAM Symposium, Zurich, Switzerland, Springer, Berlin, pp 257–274

    Google Scholar 

  24. Berman NS (1989) Large eddies and polymer strings. In: Gyr A (ed) Structure of turbulence and drag reduction. IUTAM Symposium, Zurich, Switzerland, Springer, Berlin, pp 275–281

    Google Scholar 

  25. McComb WD, Rabie LH (1982) Local drag reduction due to injection of polymer solutions into turbulent flow in a pipe. Part I: Dependence on local polymer concentration. Part II: Laser-Doppler measurements of turbulent structure. AIChE J 28:547–565

    Article  Google Scholar 

  26. Tiederman WG, Luchik TS, Bogard DG (1985) Wall-layer structure and drag reduction. J Fluid Mech 156:419–437

    Article  Google Scholar 

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Authors and Affiliations

  1. Applied Fluids Engineering Laboratory, Department of Naval Architecture and Ocean Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113, Tokyo, Japan

    Madan Mohan Guin, Hiroharu Kato, Hajime Yamaguchi, Masatsugu Maeda & Masaru Miyanaga

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  1. Madan Mohan Guin
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  2. Hiroharu Kato
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  3. Hajime Yamaguchi
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  4. Masatsugu Maeda
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  5. Masaru Miyanaga
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Guin, M.M., Kato, H., Yamaguchi, H. et al. Reduction of skin friction by microbubbles and its relation with near-wall bubble concentration in a channel. J Mar Sci Technol 1, 241–254 (1996). https://doi.org/10.1007/BF02390723

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  • DOI: https://doi.org/10.1007/BF02390723

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