experimental study of flow control on bluff body using piezoelectric actuators

Active flow control is experimentally investigated on a car-type bluff body. the actuation is basedon a synthetic jet actuator placed at the top of the ahmed body rear window. in the present paper, asynthetic jet characterization is presented, the frequencies and the optimal amplitudes with regard tothe spatial evolution are analyzed. all the measurements are carried out in a wind tunnel at reynolds numbers based on the body length between 10^6 and 3×10^6. the bluff body shows a maximum drag reduction of 10% when optimal control is applied. independent effect of the reduced frequencyand the momentum coefficient actuation parameters on the drag reduction are also detailed in thepresent paper. this reduction induces changes in the flow field due to the piezoelectric actuation.the flow topology modification is investigated via particle image velocimetry measurements in orderto estimate the flow response to a local excitation and to understand the mechanism involved in theaerodynamic drag control.