| taille du texte : S-M-L |
| impression | intranet

The effects of pulse frequency and duty cycle on the skin friction downstream of pulsed jet vortex generators in an adverse pressure gradient turbulent boundary layer

type de publication      article dans une revue internationale avec comité de lecture
date de publication 2009
auteur(s) Kostas Jim; Foucaut Jean-Marc; Stanislas Michel
journal (abréviation) Aerospace Science and Technology (Aero Sci Tech)
volume (numéro) 13 (1)
  
pages 36 – 48
résumé An investigation on the viability of pulsed jets as active vortex generator devices was conducted. The devices were installed and tested on an adverse pressure gradient turbulent boundary layer designed to simulate the suction side of a conventional aircraft wing. Both co-rotating and counterrotating jet geometries were used. The duty cycle and frequency of pulsation were varied and their effects were investigated by measuring the skin friction gains at a predefined location (the location of the minimum skin friction for the un-actuated situation) on the adverse pressure gradient turbulent boundary layer. Pulsing the jets proved to be successful in increasing the wall skin friction and therefore potentially delaying separation. The improvements in wall shear stress were approximately proportional to the duty cycle. The frequency of jet pulsation was found to be important for attaining optimal gains, however no clear relationship between frequency and shear stress gain was observed. Phase averaged wall shear stress measurements far downstream of actuation indicate that quasisteady structures are introduced by the vortex generators when actuating with a sufficiently high pulse frequency. In this situation interactions between successive structures produced by the jets were likely to be occurring.
mots clés flow control;pulsed jets;vortex generators;wall shear stress;adverse pressure gradient turbulent
lien lien  
Exporter la citation au format CSV (pour Excel) ou BiBTeX (pour LaTeX).