Flow control of annular compressor cascade by synthetic jets

An experimental investigation conducted in a stationary annular cascade wind tunnel demonstrated that unsteady flow control using synthetic (zero mass-flux) jets can effectively reduce flow separation from suction side of the blade in axial compressor cascade. The synthetic jets driven by a high-power speaker were introduced through the casing radially into the flow-field just adjacent to the leading edge of compressor cascade. The experimental results revealed that the aerodynamic performance of compressor cascade could be improved amazingly by synthetic jets and the maximum relative reduction of loss coefficient was up to 27.5%. The optimal analysis of the excitation frequency, excitation location was systematically investigated at different incidences. In order to obtain detail information on flow-field structure, DPIV technique was adopted. The experimental results showed that the intensity of wake vortices became much weaker and streamlines became smoother and more uniform by synthetic jets.