A New Class of Synthetic Jet Actuators—Part II: Application to Flow Separation Control

In this work we present the application of the new synthetic jet actuator (SJA) to flow separation control over a NACA 0015 wing. The actuator is compact enough to fit in the interior of the wing that has a chord of 0.375 m. The wing was tested in the Texas A&M University Aerospace Engineering 3 ft×4 ft wind tunnel. An experimental investigation into the effects of the synthetic jet actuator on the performance of the wing is described. Emphasis is placed on the capabilities of the actuator to control the separation of the flow over the wing at high angles of attack. The results include force balance measurements, on surface and off surface flow visualization, surface pressure measurements, and wake surveys. All of the reported tests were performed at a free-stream velocity of 35 m/s, corresponding to a Reynolds number of $8.96×105.$ The angle of attack was varied from −2.0 deg to 29.0 deg. For the results presented, at angles of attack lower than 10 deg, the actuator has minimal effects. At higher angles of attack, the SJA delays the onset of stall. The use of the actuator causes an 80% increase in the maximum lift coefficient, while the angle at which stall occurs is increased from 12 to 18 deg. The drag on the wing is decreased as a consequence of SJA actuation. For angles of attack larger than 18 deg, where the wing experiences massive separation, the SJA still provides a moderate amount of lift augmentation compared to the unforced case. At angles of attack larger than 25°, a larger frequency of actuation is required to produce significant effects.