Direct Drag and Hot-Wire Measurements on Thin-Element Riblet Arrays

  • S. P. Wilkinson
  • B. S. Lazos
Part of the International Union of Theoretical and Applied Mechanics book series (IUTAM)


An experimental study of stream wise, near-wall, thin-element riblet arrays under a turbulent boundary layer has been conducted in low-speed air. Hot-wire data show that a single, isolated thin-element riblet causes formation of counter-rotating vortex-pairs with a spanwise wavelength of 130 viscous lengths. Abrupt shifts in turbulence intensity magnitude and peak location are observed for stream wise riblet arrays as spanwise riblet spacing is varied. Direct drag measurements show net drag reduction (up to 8.5 percent) over a wide range of riblet spacings along with behavior at discrete non-dimensional spacings indicative of vortex activity. Overall, the data suggest that more than one drag reduction mechanism may be involved.


Turbulence Intensity Turbulent Boundary Layer Drag Reduction AIAA Paper Vortex Pair 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Walsh, M. J.; and Lindemann, A. M.: Optimization and Application of Riblets for Turbulent Drag Reduction. AIAA Paper No. 84–0347, January 1984.Google Scholar
  2. 2.
    Gallagher, J. A.; and Thomas, A. S. W.: Turbulent Boundary Layer Characteristics Over Stream wise Grooves. AIAA Paper No. 84–2185, August 1984.Google Scholar
  3. 3.
    Hooshmand, A.; Youngs, R. A.; Wallace, J. M.; and Balint, J. L.: An Experimental Study of Changes in the Structure of a Turbulent Boundary Layer Due to Surface Geometry Changes. AIAA Paper 83–0320, 1983.Google Scholar
  4. 4.
    Bacher, E. V.; and Smith, C. R.: A Combined Visualization-Anemometry Study of the Turbulent Drag Reducing Mechanisms of Triangular Micro-Groove Surface Modifications. AIAA Paper No. 85–0548, March 1985.Google Scholar
  5. 5.
    Khan, M. M. S.: A Numerical Investigation of the Drag reduction by Riblet Surfaces. AIAA Paper No. 86–1127, May 1986.Google Scholar
  6. 6.
    Bechert D. W.; Bartenwerfer, M.; Hoppe, G.; and Reif, W. E.: Drag Reduction Mechanisms Derived from Shark 9cin. Presented at 15th Congress, International Council of the Aeronautical Sciences, London, Paper No. 861.8.3., Sept. 1986.Google Scholar
  7. 7.
    Liu, C. K.; Kline, S. J.; and Johnston, J. P.: An Experimental. Study of Turbulent Boundary Layer on Rough Walls. Stanford University, Dept Mech. Engn., Report M D-15, July 1966.Google Scholar
  8. 8.
    Head, M. R.; and Bandyopadhyay, P.: New Aspects of Turbulent Boundary-Layer Structure. J. Fluid Mech., v. 107, 1981.Google Scholar
  9. 9.
    Kim, J.: Turbulence Structures Associated with the Bursting Event Phys. Fluids 28 (1), January 1985.Google Scholar
  10. 10.
    Nakagawa, H.; and Nezu, I: Coherent Structures in Open Channel Flow, in Structure of Turbulence in Heat and Mass Transfer, Zaric, Z. P. ed., Hemisphere Pub. Co., Washington, 1982.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • S. P. Wilkinson
    • 1
  • B. S. Lazos
    • 1
  1. 1.Viscous Blow Branch, High-Speed Aerodynamics DivisionNASA Langley Research CenterHamptonUSA

Personalised recommendations