Noise assessment and low-noise flight path planning platform for urban air mobility

The rapidly emerging market of urban air mobility has raised considerable public concern about noise exposure and annoyance, which is likely to limit the development of future aerial transportation. This study presents a comprehensive approach to evaluate the flight noise of an urban air mobility vehicle under various operating conditions and to provide practical flight strategies for low-noise path planning. Two methods with different fidelity levels are considered and compared in evaluating sound sources. The first approach is based on an efficient semi-empirical model to predict the rotor noise and a boundary element method solver to account for the noise scattering from the vehicle fuselage. The second approach is based on high-fidelity computational aeroacoustic simulations considering a practical full-scale urban air mobility vehicle. Then, a Gaussian beam method is used to calculate the far-field sound propagation considering practical physical phenomena in complex environments, including sound refraction attenuation in the atmosphere and reflection from obstacles. A low-noise flight planning strategy is proposed using a heuristic method to optimize the vehicle flight path in realistic urban scenarios. The proposed methods should contribute to future green aerial transportation in low-altitude operations.