Observations on Rotating Instabilities and Spike Type Stall Inception in a High-Speed Multistage Compressor

Figure 6

Frequency spectra of a casing pressure probe close to the rotor ~ 1 LE in comparison of three shaft rotation speeds (80% Ω, 90% Ω, and 100% Ω), “full” spectrum (a), and zoom on frequency bump (b).

(a)

(b)