A preliminary assessment of the aerodynamic and aeroacoustic impact of swirl recovery vanes (SRVs) installed downstream of a single-rotating propeller model was performed at the large low-speed facility of the German-Dutch wind tunnels (DNW-LLF). The SRVs are designed to recover the swirl in the rotor slipstream, thereby increasing the propulsive efficiency without the added complexity of contra-rotating systems. The performance data acquired with a rotating shaft balance showed that the upstream effect of the SRVs on the time-averaged rotor performance was negligible. Particle image velocimetry measurements in the slipstream of the propeller with and without SRVs substantiated the efficacy of the vanes in reducing the swirl in the propeller slipstream. Integrated in the radial direction, installation of the vanes reduced the swirl kinetic energy by 50% at a medium propeller thrust setting. An additional slipstream contraction was observed with vanes installed. The acoustic data measured with out-of-flow microphones showed that installation of the SRVs increased the total sound pressure levels by 2 to 6 dB compared to the isolated propeller.
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