The detailed three-dimensional unsteady numerical study was conducted in a transonic compressor rotor to deepen the understanding of unsteady flow phenomenon in rotor blade tip region. Unsteady numerical simulations were studied in single rotor under different inlet conditions and different mass flows

so as to investigate the complex flow structure in rotor blade tip region and the development of blade tip unsteady flow. Results showed that the structure of blade tip flow field varied under different inlet conditions. When inlet direction was non-axial

signal passage periodical form emerged for unsteady flow at blade tip

while an unsteady flow phenomenon like “rotating instability”

spreading along circumferential direction

occurred in blade tip region under axial inlet condition. And with the decrease of mass flow

the structural flow field of blade tip region changed correspondingly.