The subject of this paper concerns test results about non-synchronous vibration in a multi-stage axial compressor. The phenomenon encountered during the compressor tests is defined as an aerodynamic rotating vortex instability. It can be described as a vortex shedding mechanism in the tip region of rotor blades, which leads to high-pressure fluctuations in the flow field. The study of frequencies of this source in the fixed frame and in the rotating frame with a very high resolution (Δf = 0.37Hz) has brought very accurate results about vortex characteristic parameters. So, the aim of the paper is, first, to present test results about rotating vortex instability in a multistage axial compressor, and, in a second part, to expose the different hypothesis concerning this phenomenon. It could be defined as a progress report on which are developed all the assumptions that haven't been turned down. Nevertheless, all this assumptions can lead to different analysis and scenarios, not always consistent. Our work on this subject is still going on; tests are already forecast in order to validate our hypothesis.
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