Date of Award
Flow separation causes aircraft to experience an increase in drag degrading their aviation performance. The goal of the study was to delay flow separation on an airfoil by embedding a high-frequency translational piezoelectric actuator along the surface of the airfoil. This study investigated the extent to which the high-frequency translational piezoelectric actuator displaces the flow separation downstream or prevents it altogether utilizing a fog-based flow visualization experiment. The actuators with two actuation surfaces were embedded on the suction surface of an Eppler 862 airfoil model and placed in a low-speed wind tunnel. Dry ice fog streams were injected into the wind tunnel and illuminated by a continuous laser in order to visualize the flow. Consecutive pictures of the flow field around the airfoil were taken every 5 microseconds using a high speed camera in order to observe the flow separation phenomenon before and after turning on the high-frequency translational surface actuation. The effects of the actuation on the flow separation were observed at different surface displacements ranging up to 0.12 mm at a 565 Hz operating frequency, angles of attack ranging up to $24^o$, and wind tunnel free stream velocities increased up to 12.7 m/s. As a result, the flow visualization study confirmed that the employed high-frequency translational surface actuation had the obvious control authority on delaying or suppressing the flow separation over the airfoil depending on the parameters changed.
Okoye, Kenechukwu, "Delaying Flow Separation Using Piezoelectric Actuators" (2020). Honors Theses. 1517.
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