The mechanisms that should be considered for separation flow control applications of nanosecond pulsed dielectric barrier discharge (DBD) actuators were investigated on a NACA 0015 profile for velocities of 10 m/s (Re = 100, 000) and 20 m/s (Re = 200, 000) in ambient wind tunnel conditions. Near and post-stall angles of attack were considered (16 and 24). The dominant frequencies existing in the flow were measured. Moderate voltage levels were applied (4 and 7 kV) and the actuator was operated at these identified dominant frequencies and compared with known effective frequencies from literature. In all cases, influences by the actuator on the flow structures were observed and the operation of the actuator at the dominant flow frequencies of a stalled airfoil was shown to give control authority.