Broadband interaction noise predictions for an axial compressor stator

The broadband interaction noise of the axial compressor stator-only configuration in the Aeroacoustic Wind Tunnel (AWT) at the Leibniz University Hannover is investigated in this work. Posson’s analytical model, which uses a threedimensional rectilinear cascade response model coupled with an in-duct acoustic analogy for the subsequent acoustic propagation, is employed to estimate the noise from impinging gusts. First, a model validation with experimental results of NASA’s Source Diagnostic Test (SDT) AIAA benchmark is presented. For the subsequent compressor stator investigations, the model inputs are derived from numerical pre-tests using steady RANS simulations. Assuming homogeneous isotropic turbulence, two different models by Liepmann and Von Kármán are applied to calculate the velocity turbulence spectrum and radial correlation length. Finally, the acoustic results are evaluated by comparing the sound power spectra upstream and downstream of the compressor stator vane. The resulting differences can be related to variations in axial velocities and integral turbulent length scale for all four operating conditions. The obtained broadband interaction noise estimations of the test rig serve as a baseline for following experimental noise measurements.