|type de publication
||article dans une revue internationale avec comité de lecture
|date de publication
||Kostas Jim; Foucaut Jean-Marc; Stanislas Michel|
||Aerospace Science and Technology (Aero Sci Tech)
| || |
||36 – 48
||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.
||flow control;pulsed jets;vortex generators;wall shear stress;adverse pressure gradient turbulent