Integration of a Noise Analysis Module into a Multidisciplinary Aircraft Design Process

Author: Philip Krammer



Aircraft noise reduction can be achieved not only by noise reduction at source but also by modification of parameters in aircraft design and performance. Treating both merely independent from each other does not necessarily lead to the favoured results. As a matter of fact, a balanced approach is necessary to combine both methodologies with each other for multidisciplinary optimization. Aircraft noise analysis can be conducted with the Parametric Aircraft Noise Analysis Module (PANAM). PrADO (Preliminary Aircraft Design Optimization) provides a framework to investigate state-of-the art aircraft configurations already in an early stage of conceptual design. The objective of the thesis is the interconnection of both programs that allows for a direct response in noise impact on ground due to changes in aircraft configuration and performance. Parameters of aircraft geometry, the propulsion system and discretised trajectories are extracted out of PrADOs modules and databases. Application of the Euler turbine equation was necessary to gather fan blade tip speed from thermodynamic engine cycle analysis results. Maximum climb angle is observed by making use of the excess power. The aircraft is then “flown” to evaluate noise impact on ground. Results show not only that obtained Effective Perceived Noise Levels (EPNL) provide comparability with ICAOs noise certification reference values but also that a short- to medium range aircraft with a 40 % increase in static thrust exhibits a potential in a noise reduction during take-off. The ground area enclosed by the 80 EPNdB noise contour of constant EPNL is decreased by more than 20 % with respect to the conventional baseline aircraft. Another application of the derived interface on a larger freighter aircraft with a maximum take-off weight of about 330 tons indicates valuable results although semi-empiric, parametric noise source models are based on noise measurements of an Airbus A319. A unique visualisation of characteristic noise radiation has been conducted successfully. Changes in directivities and dimensions contribute to a generic understanding how implemented noise source models respond to changes in aircraft configuration and condition.