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 jets (zero mass flux) could effectively reduce flow separation in the axial compressor cascade. The synthetic jets driven by speaker were introduced through the casing radially into the flow-field just adjacent to the leading edge of the compressor cascade. The experimental results revealed that the aerodynamic performance of the 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 investigated at different incidences. In order to obtain detailed information on flow-field structure, the digital particle image velocimetry (DPIV) technique was adopted. The experimental results indicated that the intensity of wake vortices became much weaker and streamlines became smoother and more uniform with synthetic jets.