  This study investigates the three-dimensionality of synthetic jet flow
control over a NACA 0025 profile wing using horizontal and vertical smoke wire
visualization. The stalled flow in the baseline case is visualized, providing
insights into the shear layer roll-up process, the transition to turbulence,
and vortex shedding in the wake. In the controlled flow study, two actuation
frequencies, $F^+=1.18$ and $F^+=11.76$, are investigated, with a focus on
spanwise control authority and the role of coherent structures in flow
reattachment. The results indicate that while the control is effective at the
midspan over the entire chord length, its effect diminishes with increasing
distance from the midspan. Both control cases result in significant spanwise
velocities, observed by a contraction of the flow towards midspan. Lastly, the
high-frequency actuation results in unique small-scale structures at the shear
layer-freestream interface.
