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Effect of polymer additives on Görtler vortices in Taylor—Couette flow

Published online by Cambridge University Press:  26 April 2006

S. H.-K. Lee
Affiliation:
Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, NJ 08855-0909, USA Present address: Mechanical Engineering Department, University of Hong Kong Institute of Science and Technology, (UHKIST)Hong Kong.
S. Sengupta
Affiliation:
Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, NJ 08855-0909, USA
T. Wei
Affiliation:
Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, NJ 08855-0909, USA

Abstract

Taylor—Couette flow is ideal for studying drag-reducing polymer additives because, unlike turbulent boundary layers, the instabilities are better understood. Video records of laser-induced fluorescence experiments with and without polymers will be presented. Polyethylene-oxide (PEO) ‘oceans’ were used in concentrations of 20 and 100 p.p.m. In the Taylor number range, 3 × 104Ta ≤ 108, Newtonian flow consisted of Taylor vortices which span the gap between cylinders and much smaller Görtler vortices at the inner cylinder wall. Measurements of core-to-core separation between counter-rotating vortices were made to estimate the Görtler instability wavenumber. These measurements show that PEO addition increases the Görtler wavenumber for a given Taylor number. At the lower Taylor numbers, Görtler vortex formation was suppressed by PEO. This implies that polymers directly affect the evolution of centrifugal instabilities.

Type
Research Article
Copyright
© 1995 Cambridge University Press

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References

Fabula, A. G. 1966 An experimental study of grid turbulence in dilute high-polymer solutions. PhD dissertation, Dept. of Aero. Engng, Pennsylvania State University.
Fenstermacher, P. R., Swinney, H. L. & Gollub, J. P. 1979 Dynamical instabilities and the transition to chaotic Taylor vortex flow. J. Fluid Mech. 94, 103.Google Scholar
Giesekus, H. 1972 On instabilities in Poiseuille and Couette flows of viscoelastic fluids. Prog. Heat Mass Transfer 5, 187.Google Scholar
Goldshtik, M. A., Zametalin, V. V. & Shtern, V. N. 1982 Simplified theory of the near-wall turbulent layer of Newtonian and drag-reducing fluids. J. Fluid Mech. 119, 423.Google Scholar
Green, J. & Jones, W. M. 1982 Couette flow of dilute solutions of macromolecules: embryo cells and overstability. J. Fluid Mech. 119, 491.Google Scholar
Hayes, J. W. & Hutton, J. F. 1972 The effect of very dilute polymer solutions on the formation of Taylor vortices. Comparison of theory with experiment. Prog. Heat Mass Transfer 5, 195.Google Scholar
Hinch, E. J. 1977 Mechanical models of dilute polymer solutions in strong flows. Phys. Fluids 20, S22.Google Scholar
Lee, S. H.-K. 1990 The effect of drag reducing polymer additives on Taylor—Couette flows. MS thesis, Dept. of Mech. & Aero. Engng, Rutgers University.
Lumley, J. L. 1969 Drag reduction by additives. Ann. Rev. Fluid Mech. 1, 367.Google Scholar
Massah, H., Kontomaris, K., Schowalter, W. R. & Hanratty, T. J. 1993 The configurations of a FENE bead-spring chain in transient rheological flows and in a turbulent flow. Phys. Fluids A 5, 881.Google Scholar
Rabin, Y. & Zielinska, B. J. A. 1989 Scale-dependent enhancement and damping of vorticity disturbances by polymers in elongational flow, Phys. Rev. Lett., 63, 512.Google Scholar
Smith, G. P. & Townsend, A. A. 1982 Turbulent Couette flow between concentric cylinders at large Taylor number. J. Fluid Mech. 123, 187.Google Scholar
Sparrow, E. M., Munro, W. D. & Jonsson, V. K. 1964 Instability of the flow between rotating cylinders: the wide gap problem. J. Fluid Mech. 20, 35.Google Scholar
Swearingen, J. D. & Blackwelder, R. F. 1987 The growth and breakdown of streamwise vortices in the presence of a wall. J. Fluid Mech. 182, 255.Google Scholar
Townsend, A. A. 1984 Axisymmetric Couette flow at large Taylor numbers. J. Fluid Mech. 144, 329.Google Scholar
Walowit, J., Tsao, S. & DiPrima, R. C. 1964 Stability of flow between arbitrarily spaced concentric cylinder surfaces including the effect of a radial temperature gradient. Trans. ASME E: J. Appl. Mech. 31, 585.Google Scholar
Wei, T., Kline, E. M., Lee, S. H.-K. & Woodruff, S. L. 1992 Görtler vortex formation at the inner cylinder in Taylor—Couette flow. J. Fluid Mech. 245, 47.Google Scholar
Wei, T. & Willmarth, W. W. 1992 Modifying turbulent structure with drag reducing polymer additives in turbulent channel flows. J. Fluid Mech. 245, 619.Google Scholar
Wiest, J. M., Wedgewood, L. E. & Bird, R. B. 1989 On coil-stretch transitions in dilute polymer solutions. J. Chem. Phys. 90, 587.Google Scholar