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Flow visualization of the near-wall region in a drag-reducing channel flow

Published online by Cambridge University Press:  29 March 2006

G. L. Donohue
Affiliation:
School of Mechanical and Aerospace Engineering, Oklahoma State University Present address: Naval Undersea Research and Development Center, Pasadena, California.
W. G. Tiederman
Affiliation:
School of Mechanical and Aerospace Engineering, Oklahoma State University
M. M. Reischman
Affiliation:
School of Mechanical and Aerospace Engineering, Oklahoma State University

Abstract

The objectives of this study were to determine whether the addition of drag-reducing macromolecules alters the structure of the viscous sublayer and thereby modifies the production of kinetic energy in turbulent wall flows. This was accomplished by visualizing the near-wall region of a fully developed two-dimensional channel flow. Motion pictures were taken of dye injected into the near-wall region. Both water and a dilute drag-reducing polyethylene oxide-FRA solution were used as working fluids. The motion pictures were analysed to determine the spanwise spacing and the bursting rate of low-speed streaks that are characteristic of the viscous sublayer. The amount of drag reduction was established from pressure-drop measurements in pipe flows and a correlation that is independent of hydraulic diameter.

The data show that the time between bursts for an individual streak in a drag-reducing flow has the value for a water flow at the reduced wall shear. However, both the physical and the non-dimensional streak spacing is significantly increased in the drag-reducing flows and thus the spatially averaged bursting rate is decreased. This evidence strongly suggests that the dilute polymer solution decreases the production of turbulent kinetic energy by inhibiting the formation of low-speed streaks. A tentative explanation for this behaviour which is based upon the solution's high resistance to elongational strains and vortex stretching is offered.

Type
Research Article
Copyright
© 1972 Cambridge University Press

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References

Black, T. J. 1969 In Viscous Drag Reduction(ed. C. S. Wells), pp. 383407. New York: Plenum.
Clark, J. A. 1968 Trans. A.S.M.E., J. Basic Engng, D 90, 455.
Clark, J. A. & Markland, E. 1971 Proc. A.S.C.E., J. Hydraulics Div. 97, 1653.
Corino, E. R. & Brodkey, R. S. 1969 J. Fluid Mech. 37, 1.
Donohue, G. L. 1972 The effect of a dilute, drag-reducing macromolecular solution on the turbulent bursting process. Ph.D. thesis, Oklahoma State University.
Donohue, G. L., MCLAUGHLIN, D. K. & TIEDERMAN, W. G. 1972 Phys. Fluids (to be published).
Donohue, G. L. & Tiederman, W. G. 1971 The effect of a dilute, drag-reducing macromolecular solution on the viscous sublayer of a turbulent channel flow (16mm motion picture). Submitted to Asme/ESL Film Library, New York.
Eckelman, L. D., Fortuna, G. & Hanratty, T. J. 1972 Nature, 236, 94.
Fortuna, G. 1971 Effect of drag-reducing polymers on flow near a wall. Ph.D. thesis, University Illinois.
Fortuna, G. & Hanratty, T. J. 1972 J. Fluid Mech. 53, 575.
Gadd, G. E. 1965 Nature, 206, 463.
Gupta, A. K., Laufer, J. & Kaplan, R. E. 1971 J. Fluid Mech. 50, 493.
Halleen, R. M. & Johnston, J. P. 1967 Stanford University Rep. MD–18.
Hussain, A. K. M. F. & Reynolds, W. C. 1970 Stanford University Rep. FM–6.
KIM, H. T., Kline, S. J. & Reynolds, W. C. 1971 J. Fluid Mech. 50, 133.
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 J. Fluid Mech. 30, 741.
Laufer, J. & Badri Narayanan, M. A. 1971 Phys. Fluids, 14, 182.
Lumley, J. L. 1969 In Annual Reviews of Fluid Mechanics, vol. 1 (ed. W. R. Sears), pp. 367384. Annual Reviews Inc.
Merrill, E. W., Smith, K. A., Shin, H. & Miceley, H. S. 1966 Trans. Soc. Rheology, 10, 335.
Moretti, P. M. & W. M. 1965 Int. J. Heat & Mass Transfer, 8, 1187.
Paterson, R. W. & Abernathy, F. H. 1970 J. Fluid Mech. 43, 689.
RAO, K. N., Narasimha, R. & Badri Narayanan, M. A. 1971 J. Fluid Mech. 48, 339.
Rudd, M. J. 1972 J. Fluid Mech. 51, 673.
Runstadler, P. W., Kline, S. J. & Reynolds, W. C. 1963 Stanford University Rep. MD.8
Virk, P. S. 1971 J. Fluid Mech. 45, 417.
Wallace, J. M., Eckelmann, H. & Brodkey, R. S. 1972 J. Fluid Mech. 54, 39.
Walsh, M. 1967 On the turbulent flow of dilute polymer solutions. Ph.D. thesis, California Institute of Technology.
Wells, C. S. & Spangler, J. G. 1967 Phys. Fluids, 10, 1890.
Whitsitt, N. F., Harrington, L. J. & Crawford, H. R. 1969 In Viscous Drag Reduction (ed. C. S. Wells), pp. 265280. New York: Plenum.