This paper presents one of the main objective of WP1 of Clean Sky GRC5 MANOEUVRES project, which consists in the correlation of ground noise data measured during flight tests, with numerical predictions obtained by a numerical process aimed at the analysis of the acoustic field emitted by helicopter rotors in arbitrary unsteady manoeuvring flight. Two of the helicopter trajectories analysed by the dedicated GRC5 flight test campaign are considered. Noise measurements obtained by microphones located on the ground at several positions along and aside the ground projection of the vehicle fly-over trajectory are used for correlation. The numerical simulation starts with the aeromechanic identification of the flown trajectory, followed by the corresponding prediction of aerodynamic loads, rotor noise radiation and far field atmospheric propagation.@en

One of the main factors that limit public acceptance of rotorcraft is the noise emitted over densely populated areas, which prevents a wider diffusion of these vehicles capable of performing flight operations otherwise unattainable. It is the result of complex phenomena generated aerodynamically, through the main and tail rotors, as well as mechanically, by the engine and transmission system. Significant research effort is currently made for reducing rotorcraft acoustic impact, both by helicopter manufacturers and by research institutes and academia.@en