Comparative Investigation of Predictive Capability of Aeroacoustic Methods for Single Rotation Propellers

The sound-pressure field of a propeller consists mainly of (i) thickness noise caused by volume displacement of the air by the blades and thus is defined by the blade geometry and (ii) loading noise due to forces that the blades impose on the air and thus determined by blade loading which may be steady or unsteady. However, the possible contribution of an additional noise source due to non-linear effects (iii) needs to be considered in the case of high tip speeds. This report deals with a comparative study of propeller acoustic codes developed by various GARTEUR partners (AS, DAP, DLR, FFA, NLR and ONERA) and their comparison with experimental results. The present work is restricted only to the dicrete components of propeller noise and no attempt is made to examine the less important broadband component. Two propellers are chosen for this study. One propeller (Hartzell) represents the conventional