Experimental and numerical study of a finlet-like biomimetic structure-integrated propeller.

The aerodynamic noise generated by propellers remains a major challenge for unmanned aerial vehicle (UAV) propulsion systems, simultaneously constraining their stealth capability and energy utilization efficiency. Although propellers incorporating biomimetic designs, such as leading-edge (LE) or trailing-edge (TE) serrations, have demonstrated certain potential for noise mitigation, these approaches are often accompanied by reductions in aerodynamic efficiency or compromised power-consumption performance. To address this issue, this study proposes a finlet-like biomimetic structure-integrated propeller (FLBP), which integrates the flow-conditioning capability of a finlet-like biomimetic structure (FLBS) inspired by fast-swimming fish. Experimental results show that, compared with the baseline propeller (BP), the FLBP exhibits superior overall performance, achieving a maximum noise reduction of 3.69 dB while simultaneously reducing power consumption by up to 6.89%. Spectral analysis further reveals that the FLBS effectively suppresses the discrete tonal noise at the blade passing frequency (BPF) and attenuates broadband noise above 2 kHz. The observed performance enhancement is attributed to the synergistic flow-field regulation induced by the FLBS, including vortex generation, modulation of turbulence development, and enhanced vortex breakdown and dissipation. These findings provide useful insights for the biomimetic optimization design of low-noise, high-efficiency UAV propellers.