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To show the influence of the synthetic jet on the wake of a cylinder and the aerodynamics performances, a piston-rod-crank actuator was designed to provide a synthetic jet with amplitude up to 20% of the free-stream velocity from the wind tunnel. The rod is driven in rotation by an electrical motor with variable frequency and maximum speed of 2800 rev/min corresponding to a frequency of 47 Hz.

Active control of flow over a cylinder at Re=1800, based on the free-stream velocity U∞=0.67m/s, and cylinder diameter d=40mm, is carried out using a synthetic jet. The slot injectors are positioned at θinj = ± 70°. An actuator was used to produce a synthetic jet by exciting a cavity with an alternative piston system. The results show that for the frequency of control located around the natural frequency of the vortex emission a phenomenon of lock-in appear.