INTERACTION OF THE ROTOR BLADE SHOCK WAVES IN SUPERSONIC COMPRESSORS WITH UPSTREAM STATOR VANES.

The shock waves formed at the leading edge of the rotor blades of a supersonic axial compressor with subsonic absolute velocity move with these blades and simultaneously propagate upstream in the zone of the inlet guide vanes. These waves are diffracted and reflected on the vanes, inducing instationary pressure distributions which cause two main effects: a mean force on every vane corresponding to a supplementary flow deflection in the stator, and unsteady efforts on the vanes which may constitute a possible excitation of vibrations in bending and torsional modes. A good estimation of these effects is made from a complete analysis of the elementary case of the interaction between an ideal wave and an isolated stator vane. Optical Schlieren measurements confirm the theoretical analysis.