[hal-01073973] EXPERIMENTAL INVESTIGATIONS ON FLUIDIC CONTROL OVER AN AIRFOIL

This study presents the development of two fluidic actuators − namely microjets and tangential blowing actuator TBA designed for flow separation control The developed actuators are compact enough to fit inside an ONERA D profiled wing with a chord of 035 m Test bench experiments showed that the microjets resp TBA were able to produce exit velocities up to 330 m/s resp 60 m/s These actuators were placed in the model and were tested in wind tunnels for various blowing rates The investigations included the use of force balance measurements on-surface flow visualization with pigmented oil off-surface flow visualizations with smoke surface pressure distribution measurements and Particle Image Velocimetry PIV Most of the tests were performed at free-stream velocities between 20 m/s for PIV and 40 m/s corresponding to Reynolds numbers in the range 047 × 10^6−093 × 10^6 The angle of attack varied from −2 to 20 degrees Experiments were conducted using the naturally occurring laminar boundary layer as well as for a turbulent boundary layer In such a case rough strips were used in the vicinity of the leading edge The present tests show the efficiency of these devices to delay separation and improve aerodynamic performances of the wing for example a maximum of 30% gain in CL has been reached using the microjets Both actuators tend to increase the lift coefficient CL after stall and areas of separated flow have been eliminated by applying control as suggested by flow visualizations and PIV velocity fields



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