Identification of Low-Pressure Compressor Blades Flutter

The unstable oscillations during coaxial low-pressure compressor blade flutter has been examined. The spectral analysis of strain gage records of blade oscillations and synchronous records of pressure pulsations in the countercurrent air flow shows that the damping of oscillation modes is the most informative parameter defining the flutter's evolution process. The coincidence of the eigenfrequencies of the blades and the synchronous character of the changes in the time relationships of damping at the eigenfrequencies frequencies of the blade, and at the frequencies of acoustic diametrical modes of pressure pulsations occurring in the air flow shows that the phenomenon of flutter relates to the blades collective oscillation.