Rotating stall and surge have been stabilized in a transonic single-stage axial compressor using active feedback control. The control strategy is to sense upstream wall static pressure patterns and feed back the measured signal to an annular array of twelve separately modulated air injectors upstream of the rotor. At tip relative Mach numbers of 1.0 and 1.5, the control achieves a 11% and 3.5% reduction in stalling mass flow respectively. With control, the steady amount of injected air is equal to 3.6% of the design compressor mass flow. At a tip Mach number of 1.0 the stall inception dynamics and effective active control schemes are similar to results for low-speed axial compressors. The range extension can be achieved by individually damping the first and second spatial harmonics of the pre-stall rotating stall perturbations using constant gain feedback. The pre-stall dynamics are different at a tip Mach number of 1.5 than at the lower speed.
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