An experimental study of aerodynamic damping characteristics of a compressor annular cascade in high speed flow and the visualization of annular cascade flow

To clarify experimentally the characteristics of aerodynamic damping of a compressor cascade in high speed flow, which is an important factor of blade oscillatory fatigue, the time-variant aerodynamic pressure acting on the blade surface of harmonically oscillated annular cascade in torsional mode was measured with a Freon gas annular cascade test facility over a range from high subsonic to supersonic and over a wide range of reduced frequencies. Through these data, the variance of cascade aerodynamic stability of inlet flow Mach No. and reduced frequency, and the effects of shock wave movement due to blade oscillation on an unsteady aerodynamic force and on an aerodynamic stability of the cascade were made clear. The visualization of annular cascade flow by the new schlieren system is also described.