Immission-Based Noise Reduction within Conceptual Aircraft Design

Abstract

The noise on the ground not only depends on the aircraft design itself, but also on the observer location and the operating conditions of the aircraft along its flightpath. Therefore, it is inevitable to consider the individual flightpaths of each aircraft concept. This allows to fully assess the noise reduction potential for the community. In order to compute individual low-noise flightpaths for different aircraft concepts, the tool Flightpaths for Noise Analyses (FlipNA) is developed and integrated into an existing noise prediction process. The application of FlipNA focuses on three existing tube-and-wing aircraft. One aircraft is conventional, whereas two aircraft feature an engine position that offers significant fan noise shielding. To also consider different engine types during departure, two other aircraft of the Collaborative Research Center 880 are assessed. Results show that noise reduction is achieved for all three aircraft when individual low-noise flightpaths are used. Along the departure flightpaths, the noise on the ground of the two new aircraft is significantly lower compared to the conventional aircraft. The assessment of different engine types along departure flightpaths shows, that the operating conditions for minimum noise significantly depends on the engine performance and its specific noise characteristics. In summary, the necessity and benefit of considering individual flightpaths and the noise source ranking within the conceptual aircraft design phase is demonstrated. Only then can the full noise reduction potential of individual aircraft be exploited.