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)

Summary

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.

Keywords

Vortex Roted 

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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

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