The unsteady flow in a low speed compressor with repeated stages was simulated by numerical simulation of 3-D viscous flow.The influence of clocking and the interaction of wake

boundary layer and leakage vortex were discussed.The results show that only a 0.1% overall efficiency variation due to clocking of the second stage stator is found

and it is considered that the clocking effects in low speed compressor is not distinct.The unsteady flow indicates that the upstream wake can influence the boundary layer

wake and leakage flow of the downstream flow.