This paper presents the interaction between blade vibration and
part-span rotating stall in a multi-stage high speed compressor. Unsteady
aerodynamic and aeroelastic simulations were conducted using
URANS CFD. Steady state computations showed short length
scale disturbances formed local to the tip of a front stage rotor. Using
a full annulus model, these disturbances were shown to coalesce
into flow structures rotating around the annulus at approximately
76% of the shaft rotational speed. Natural evolution of the rotating
stall did not result in a coherent spatial pattern. Subsequent analyses
carried out with prescribed rotor blade vibration showed a spatial
‘lock-in’ event where the circumferential order of the part-span
rotating stall shifted to match that induced by the vibration mode.
Moreover, in contrast to its natural form in the absence of vibration,
the fully developed rotating stall showed a coherent stall signal.