Abstract: A method is provided to predict how the rotating stall will develop in axial compres-sion systems with both uniform and nonuniform inlet flow,and the rotating stall transient and its growth proeess with both uniform and cireumferential total pressure distorted inlet flow are in-vestigated in detail.It has been found that the rotating stall is preeeded by a period which will last for 40～100 rotor revolutions and in which small amplitude waves travel around the circumfer-ence and evolve smoothly into rotating stall without sham change in phase or amplitude. The throttle ramping and the inlet distortion have a crucial effect on the period and stall transient.

Key words: rotating stalls, distortion, actuator disk