Краткое описание

The influence of periodic excitation from a synthetic jet actuator on the flow separation over a NACA 0025 airfoil at an angle of attack of 10° was investigated. Experiments were performed in a low-speed wind tunnel at a chord-based Reynolds number Re_c = 10⁵. At Re_c = 10⁵, the boundary layer separates and fails to reattach at angles of attack from 0 − 10°. When the boundary layer was forced at a momentum coefficient C_µ = 2.47 × 10⁻² and excitation frequency f_e = 970 Hz, the vortex shedding associated with the uncontrolled case was eliminated and the drag coefficient was reduced by 22%. These results were compared to previous work at α = 5° on the same airfoil by Goodfellow et al. (2012), who found that a drag reduction of 52% was achieved at C_µ = 3.09 × 10⁻³. The results suggest that as the angle of attack is increased from 5° to 10°, the synthetic jet actuator must transfer more momentum to the separated boundary layer in order to cause drag reduction.