The objective of the present work is the development, the validation and the implementation of synthetic jet actuator. The slot of the synthetic jet had an angle of 45°. The performances of this actuator were estimated in a quiescent environment by using the hot wire anemometry and the PIV. The effects of the frequency and the amplitude of the actuator velocity were analyzed. The maximum velocity amplitude was obtained for a frequency around 60 Hz. This velocity can reach 28 m /s. To analyze the effect of the synthetic jet on a transverse separated flow, several tests were conducted in a wind tunnel on an inclined ramp at a variable angle . In these conditions, the separation of the flow begins at an angle of 22°. =30° and =35° were chosen to perform flow separation control. Without control the flow is characterized by the formation of a separation bulb. The size of this bulb depends on the velocity and the angle of inclination of the ramp. When the control is on, the flow is analyzed according to the jet velocity, the velocity of the cross-flow and the angle of inclination of the ramp. Results show the high potential of the actuator to reduce the size of the separation zone for angles less than 35 °. For higher angle, the actuator promotes the increase of this separation and hence the separation becomes very strong.