  This study investigates the aerodynamic effects of low- and high-frequency
synthetic jet control strategies on a National Advisory Committee for
Aeronautics (NACA) 0025 airfoil. Visualizations and measurements are employed
to assess the stability of the flow, focusing on the shear layer and wake
dynamics under two forcing frequencies. High-frequency actuation is found to
induce steadier flow reattachment and more favorable aerodynamic
characteristics compared to low-frequency control. Flow structures resulting
from high-frequency actuation, notably vortex rings, are identified and their
significance in flow control is evaluated. Furthermore, the spanwise control
authority is analyzed, revealing variations in aerodynamic stability away from
the midspan. Insights from modal analysis provide additional understanding of
flow structures and their evolution across different spanwise planes.
