KM Turbulenz
Aeroacoustics of a Commercial Drone
Noise emissions are one of the major challenges for modern commercial drones, especially in urban environments where tonal rotor noise is perceived as particularly disturbing. In multi-rotor UAVs, complex interactions between rotors and the vehicle body strongly influence both aerodynamic performance and acoustic radiation.
In this study, we investigate the aeroacoustic behavior of a commercial quadrotor drone (DJI Mini 3) using high-fidelity simulation methods. The focus lies on understanding how rotor–body interaction and rotor phase synchronization influence tonal noise generation.
Drone noise is dominated by strong tonal components at blade-passing frequencies (BPF), which are highly sensitive to:
- Rotor–rotor interaction
- Rotor–body interaction
- Phase synchronization between rotors
Due to the complex geometry of modern drones, with tilted axes and vertically offset rotors in order to be able to fold and carry the drone, these effects are difficult to predict without detailed numerical simulations.
We performed a comprehensive aeroacoustic analysis using the MGLET CFD/CAA solver, with a total of 128M cells, half of which are used to resolve the volume which the rotors sweep. 12 revolutions are simulated with a cost of 16000 CPUh.
The simulation results show good agreement with experimental measurements. In particular, the predicted spectra accurately reproduce the dominant BPF peaks and overall noise characteristics. The base noise level in the measurements are higher, since they are conducted in an open field.
Following the validation against experimental measurements, the simulation setup is used to investigate the influence of rotor phase synchronization and rotor–body interaction on the acoustic behavior of the drone.