Cyclostationary Analysis of Fan Noise Influenced by an Inflow Control Device

Acoustic data measured in a fan test facility with and without an inflow control device (ICD) over the inlet were analyzed using cyclostationary analysis technique, which separates total power into rotor-locked fluctuating component. Measurements taken mode detection ring upstream of rotor far-field microphones for configurations subsonic supersonic blade tip speeds. The ICD reduces component stabilizes frequency spectrum at passing its harmonics way that amplitudes Tyler–Sofrin modes increase, whereas neighboring orders are suppressed. distribution intermode coherence also changed, changes directivity when is installed. It demonstrated powerful tool to investigate acoustic effect on turbofan noise, revealing more details about temporal spatial structures generated sound field than classical spectral analysis.