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Experiments in Fluids

, Volume 47, Issue 1, pp 19–26 | Cite as

Active control of the turbulent drag by a localized periodical blowing dissymmetric in time

  • Sedat F. TarduEmail author
  • Olivier Doche
Research Article

Abstract

Experimental results on the reaction of the near wall turbulence and drag to a localized time periodical blowing are reported. The injection velocity is periodical and dissymmetric in time, with a rapid acceleration phase followed by a slow deceleration one. The flow is relaminarized during 70% of the oscillation period mainly during the deceleration phase. The latter maintains stable the vorticity layer induced by the blowing and prevents its roll-up contrarily to a sinusoidal time periodical blowing. Thus, a time mean drag reduction of 50% is obtained in the region recovering 200 wall units downstream of the blowing slot and this is 40% larger than the drag reduction obtained by a steady blowing with the same time mean severity parameter. The dissymmetric blowing annihilates considerably the wall turbulence activity and gives better results in terms of drag reduction compared with steady and sinusoidal blowing.

Keywords

Vorticity Wall Shear Stress Drag Reduction Injection Velocity Wall Unit 
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.

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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Laboratoire des Ecoulements Géophysiques et Industriels, LEGIGrenoble CedexFrance

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