Integration of a Noise Analysis Module into a Multidisciplinary Aircraft Design Process
Author: Philip Krammer
Thesis
Abstract
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.