Near-field sound propagation and the installation effects of an urban air mobility vehicle

Abstract

A unique challenge of the urban air mobility noise assessment is the configuration-dependent acoustic signature of different designs, of which the installed noise sources must be considered. This work presents a computational aeroacoustics study of a four-rotor urban air mobility vehicle, focusing on near-field propagation considering the installation effects of different vehicle components. The aerodynamic noise sources are computed using the delayed detached eddy simulations, in which the interactional aerodynamics of the rotating propulsion sources and the airframe are addressed. The acoustic propagation effects are calculated by solving Pierce’s equation using the computed mean flow fields and the surface noise sources. The proposed approach is expected to capture the noise scattering from the rotor supports and the fuselage, which cannot be simulated by conventional computational fluid dynamics. The near-field results are then extrapolated to the far field and compared with those from the Ffowcs-Williams and Hawkings acoustic-analogy-based solver. This research provides an integrated aerodynamic and acoustic effects evaluation which should benefit low-noise vehicle design.