A mechanism study of duty-cycled plasma actuations over a 20癱ircular-cone-cylinder model using a pair of Single-Dielectric-Barrier-Discharge (SDBD) plasma actuators and unsteady pressure tappings. The tests are carried out in a low-turbulence 3.0 m ?1.6 m low-speed wind tunnel at an angle of attack of 45? The Reynolds number based on the cone base diameter is 50, 000. The frequency of the duty cycle is 10 Hz. The convergence and salient features of the phase-locked averaged pressures at various duty cycles are studied and compared with ensemble-averaged pressures.