UDC 531.3, 533.6, 534.1 TRANSIENT PROCESS FEATURES DURING FLUTTER OF AXIAL TURBOCOMPRESSOR ROTOR BLADES © O.B. Balakshin, DcS, professor, Blagonravov Mechanical Engineering Research Institute of the RAS, Moscow, Russia B.G. Kukharenko, PhD, assoc. professor, Blagonravov Mechanical Engineering Research Institute of the RAS, Moscow, Russia Abstract. <...> Excitation conditions of blade bending flutter and air flow pressure pulsations are under study after blade resonance on torsion frequency. <...> Two subsystems of axial turbo compressor having part in flutter: rotor stage blades and compressible air flow have different dynamical features. <...> In the subsystems unstable processes evolve with time-delay. <...> For axial turbo compressor under study, it is demonstrated by leading growth of several blade oscillation and air flow pressure pulsation short-time energy in reference to other rotor blade oscillation short-time energy, and it means short time-delay of blade oscillation synchronization at appearing flutter. <...> Time warping and scaling blade oscillation and flow pressure pulsation energy records uncovers exciting sources of blade flutter as air flow pressure pulsations. <...> Keywords: blade flutter, acoustic diametral modes, short-time energy, oscillation synchronization, time warping, record scaling, axial turbo compressor. 1. <...> INTRODUCTION Experimental studies demonstrate that oscillation instability of axial turbo compressor rotor stage blades couples to air f low compressibility, appearance of its pressure pulsations, and as result to an increase of air f low elasticity between the rotor stage neighboring blades [1]. <...> As usual a resonance on blade natural frequency excited by a rotor rotation frequency harmonic precedes the blade flutter [2]. <...> As the rotor rotation frequency increases, the evolving resonance discontinues at appearing f lutter, i.e. blade synchronous oscillations. <...> Rotor has a circular symmetry, which constitutes a base of blade synchronous oscillations. <...> In the blade synchronous oscillation model, rotor stage neighboring blades oscillate with an equal frequency and constant phase shift. <...> Let be vector representing rotor blade degrees of freedom, Nb represented by decomposition on circular modes where . (2) In (1) and (2) order m <...>