FLOW CONTROL OVER A RAMP USING ACTIVE VORTEX GENERATORS

A parametric study of separation control using continuous jets vortex generators was conducted on a twodimensional ramp with a mild adverse pressure gradient on a 2 m flat plate and a flow separation on a flap. Two jets diameters were investigated : 6 and 12 mm. For both diameters, co and counter-rotating arrangements were analysed. The control efficiency was quantified by wool-tufts visualisations and by four friction probes placed on the flap. It was found that a skewness of the output voltage of a friction probe greater than -0.4 is characteristic of flow reattachment. Different spacing between jets, different pitch angles, different distances of the jets to the separation line and different VR were tested. The best configuration obtained is a counterrotating one, with δ = 0.03, λ Φ = 27.3, L Φ = 15 and α = 135 ◦.