Acoustic versus aerodynamic installation effects on a generic propeller-driven flying architecture

The present work addresses the combined aerodynamic and acoustic installation effects observed as a subsonic propeller is partly crossing the near-wake of a wing. Only the tonal noise at multiples of the blade passing frequency is considered. The aerodynamic effect is the onset of additional sound sources caused by blade-wake interaction, compared to the case of the isolated propeller. The acoustic effect is the scattering by the wing. The work is aimed at demonstrating the ability of analytical models to estimate separately these effects, which is of primary interest for the preliminary design steps of a system. A basic experiment carried out in an anechoic, open-jet facility, is described, for validation purposes. The far-field sound measurements are compared to the predictions and some key outcomes are presented. In particular, the model provides guidelines to avoid configurations of excessive noise.