UDC 531.3, 533.6, 534.1 AIR FLOW ELASTICITY IN AXIAL TURBO COMPRESSOR © O.B. Balakshin DSc, professor, Blagonravov Mechanical Engineering Research Institute of RAS, Moscow, Russia B.G. Kukharenko PhD, Assoc. professor, Blagonravov Mechanical Engineering Research Institute of RAS, Moscow, Russia D. Peitsch Professor, Technical University Berlin, Germany In present paper both flow pressure pulsations related to forced torsion oscillations and to bending flutter of rotor blades in axial turbo compressor are under study. <...> The spectrum of flow pressure pulsations respective to bending flutter contains nonlinear acoustic diametral mode frequencies related to the flutter frequency. <...> Time-dependent damping ratio demonstrates that in case of the unstable bending flutter, the respective nonlinear acoustic diametral modes stabilize the flutter amplitude locally in time. <...> Keywords: blade modes, forced oscillations, flutter, Navier-Stokes equations, Reynolds ensemble-averaging, flow nonlinearity, axial turbo compressor. 1. <...> NON-STATIONARY AIR FLOW AND FORCED TORSION OSCILLATIONS OF ROTOR BLADES As axial turbo compressor rotor rotation frequency increases, the axial air flow is compressed and its aero elasticity increases also. <...> A correlation appears between oscillations of rotor adjacent blades, and the blade oscillations became collective in nature. <...> As shown in [1], instability of rotor blade oscillations in axial turbo compressor is related to instability of respective air f low pressure pulsations. <...> In present paper both f low pressure pulsations related to forced torsion oscillations and to bending flutter of (blisk) rotor blades in axial turbo compressor are under study. <...> The analysis of non-stationary flow pressure pulsations is based on Reynolds ensemble-averaging of the flow field characteristics. <...> For the flow in axial turbo compressor, Reynolds ensemble-averaging is provided by mean of instant scalar and vector flow fields at timeevents, which differ in rotor rotation sequential periods [2–3]. <...> Reynolds ensemble-averaging provides deterministic (coherent) non-stationary flow density , (1) circum ference) of instant flow velocity field the density weighted ensemble-averaged field (Favre averaging) is in use nents v(z, r, , t), ={z, r, } ( – angle <...>