Based on the real total pressure distortion

the influence of relative position of inlet distortion on fan flow field under nonuniform clearance was studied. The results showed that there was a phase lag between the rotor flow filed and the inlet flow distortion

which was about 90°. The total pressure distortion resulted in the most remarkable effect when it acted at the circumferential position with the worst flow of the original flow field

and the rotating stall was closely related to the sector with convergence clearance. It can be inferred that the stall will occur once the overflow with high entropy has not been dissipated during the propagation from large to small clearance region.