Impact of finlet integration on propeller aeroacoustic and aerodynamic characteristics: An experimental assessment

This study experimentally investigates the impact of finlet integration on the aeroacoustic and aerodynamic characteristics of a T-MOTOR 18*6.1 carbon fiber propeller operating at low Reynolds number regimes. Far-field noise and thrust measurements were conducted under static conditions across rotational speeds ranging from 2000 to 6000 RPM and various sound radiation polar angles. Aerodynamic results indicated that finlet integration led to an average thrust performance reduction of 8% across the entire operating range, primarily attributed to increased profile drag. From an aeroacoustic perspective, findings revealed a strong dependency of finlet performance on both propeller rotational speed and noise propagation angle. Notably, finlets at 2000 RPM resulted in broadband noise reduction at high frequencies across all polar angles. Their optimal aeroacoustic performance was observed at lower rotational speeds (2000 RPM) and suction-side polar angles, particularly at 30°, where the broadband noise reduction averaged approximately 6 dB at low frequencies and 3.5 dB at high frequencies. While a tonal noise increase of approx. 1.5 dB occurred at the first blade passing frequency at this speed, the study indicates an influence on flow patterns and pressure fluctuations, inferred from the acoustic and thrust results. However, further optimization of finlet design and selection is essential to expand their beneficial impact across diverse operating conditions.