Aircraft Noise Shielding Assessment: The creation of a software tool to predict aircraft noise shielding

The amount of air traffic is increasing and cities become more and more populated. Since airports tend to be located close to or inside cities, an increasing amount of people suffer from aircraft noise pollution. More silent aircraft are needed to be able to reduce this noise pollution. One way to do this is through blocking the engine noise propagation with elements of the aircraft itself such as the wings. This method is called aircraft engine noise shielding To be able to shield the aircraft engine noise efficiently, a noise shielding assessment tool is required. In this thesis project, such a tool is developed for conventional tube with wing aircraft. This tool needs to have low computational cost while the accuracy should be sufficient for the preliminary design. To create a fast and accurate noise prediction tool, the aircraft's fuselage is modelled as a cylinder and the wings as planar surfaces. The engine is represented by a monopole sound source. The most suitable noise shielding calculation methods are found to be the barrier shielding method for the wings and the analytic solution of a cylinder for the fuselage. The noise shielding assessment tool is validated against results obtained with the Kirchhoff theory of diffraction. The noise shielding prediction tool developed in this thesis project has shown to be able to determine the noise attenuation by a point source of different aircraft configurations with low computational cost. The addition of the analytic results of the cylinder to the barrier shielding method has increased the accuracy by including the creeping rays. Keywords: Noise, Shielding, Barrier, Attenuation, Scattering, DiffractionANCEAerospace Engineerin