Active Control of a Planar Offset Attaching Jet Using Synthetic Jets

A planar jet issued from a contoured nozzle was forced using a pair of synthetic jet actuators located along the upper and the lower edges of the jet exit. The forcing frequency varied from f Hj/Uo of 0.08 to 0.45 for a fixed forcing amplitude u′/U of 0.3. It was found that the time-averaged re-attachment length was reduced by forcing, the decreases were particularly large when the lower actuator was used. The flow field was modified significantly by the forcing when f Hj/Uo was 0.08, strong vortical structures were observed in the flow which increased the turbulent fluctuations along both shear layers.