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

Abstract

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 case of high tip speeds. Broadband noise is not included. 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. Two propellers are chosen for this study. One propeller (HARTZELL) represents the conventional general aviation type while the second (R3/1) is an unswept research propeller with enhanced transonic effects at high speeds compared to swept wing.