Monopole Diffraction by Generic Plane Geometries

Abstract

The aircraft industry is facing growing complaints on aircraft noise from the residents around airports. Therefore novel aircraft architectures ("Low Noise Aircraft" - LNA) with unconventional engine positioning are considered to benefit from engine noise reduction through shielding effects. During a one year cooperation between DLR and Airbus France, an effort was undertaken to select the best methodology for the assessment of noise shielding effects for LNA configurations. The main achievements of this cooperation were (i) the benchmarking of already available tools for the prediction of noise shielding effects and (ii) the generation of an experimental database for validation. In a "Rear-Fuselage-Nacelle" configuration the engines are mounted above the rear part of the fuselage. For such a configuration, a shielding effect is expected from the fuselage and the empennage. In this article, we will focus on the shielding effect by the empennage. For an initial estimation of noise shielding, the overall aircraft contour can be simulated by simplified geometries and the engines be represented by idealized compact noise sources.