Acoustic Mode Decomposition of Compressor Noise under Consideration of Radial Flow Profiles

§To explore the sound generating mechanisms of turbomachinery like turbines or compressors in rig tests, the sound field radiated in the inlet or outlet duct is acquired by means of a sensor array and fitted to a theoretical model of the modal sound field. For this purpose, an analytical model with a uniform radial flow profile is usually deployed. This paper presents the derivation of an alternative sound field model under consideration of a realistic radial flow profile. The new model, which has to be solved numerically, was fitted against experimental data acquired in the inlet of a three-stage low pressure compressor, yielding the amplitudes of all radiated modes. The results are compared with the outcome of the classical radial mode decomposition approach basing on the analytical model.