12th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
A computed prediction of the tonal noise generated in the fan stage of an aero-engine is presented. This paper focuses in particular on unsteady fan stage aerodynamics, which leads to the generation of noise. It is further shown that there are a variety of sources of tonal noise and that, for a more complete analysis of the fan stage tonal noise balance that is due to rotor and stator interaction, these sources should be evaluated simultaneously. The computational model has been validated against steady state aerodynamic measure-ments and measured sound pressure levels. Some acoustic theory is also presented to explain the in-duct radiation behaviour of fan stage tonal noise towards the external envi-ronment.