无人机系列化旋翼气动噪声特性对比研究

The aerodynamic noise generated by rotors is a major source of noise in various rotor-based unmanned aircraft systems. In order to reduce the overall noise and enhance the acoustic stealth performance of unmanned aircraft, a comparative study of aerodynamic noise characteristics was presented for a series of equi-diameter rotors of a specific unmanned aircraft in this paper. Numerical models were established for Large Eddy Simulation to predict the aerodynamic noise characteristics of each rotor, taking the obtained surface pressure fluctuations as the acoustic input to solve the FW-H equation. The far-field noise characteristics of equi-diameter (3R) rotors were calculated and experimentally validated at different orientations. Compared to experimental results, the simulation results of sound pressure level show that the error is less 4.3% between two methods at the equi-diameter locations for five rotor models. The aerodynamic noise exhibits pronounced dipole characteristics, and the radial sound pressure level is significantly higher than the axial value. The aerodynamic noise level of different rotors is positively correlated with rotor torque, while the relationship with rotor lift is less significant.