Full-annulus unsteady simulations were performed on a subsonic axial compressor rotor

and the detailed flow parameters at near stall condition were achieved.Ten numerical static pressure probes arranged in front of the leading edge could detect two pressure disturbances

one of which was developed into a spike wave.According to analysis of the flow field

tip secondary vortexes exist in almost all passages near the blade tip and the most violent one appears in the disturbing areas.Tip secondary vortex could force tip clearance flow to form “leading edge spilling flow” and “trailing edge back flow”.The movement of the pressure disturbance along circumference was caused by the spreading of tip secondary vortex from one passage to the next.Continuous growth of tip secondary vortex in its spreading finally led to formation of spike wave.The phenomenon that the “trailing edge back flow” goes through the inlet and spills into the adjacent passage under the blade tip can be regard as the symbol of spike emergence.