Impeller-diffuser interaction:: analysis of the unsteady flow structures based on their direction of propagation

The present study is focused on the analysis of the deterministic fluctuations arising from the rotor-stator interaction within a transonic centrifugal compressor stage. A spectral analysis applied to the unsteady flow field leads to the values of the rotation speed of most energetic modes. From these values, the various structures are classified according to their direction of propagation which leads to a comprehensive description of the underlying mechanisms involved in the interaction.