Sound quality analysis of virtual aircraft prototypes: framework development and application

With the growing demand for air transportation, noise pollution from aircraft operations emerges as a public health concern in urban areas. Thus, mitigating perceived aircraft noise becomes a key objective for ensuring the sustainable growth of the aviation sector. To support this goal, it is necessary to establish assessment methodologies capable of integrating human perception as early as possible into the development process of aircraft technologies. In this contribution, a framework for sound quality analysis of virtual aircraft prototypes is proposed. First, an auralization tool is developed to render audio signals of virtual aircraft flyovers at receiver positions on the ground. For this purpose, sound source descriptions from a well-established aircraft noise prediction tool are converted into audio signals using sound synthesis techniques, while a ray-tracing software is employed to simulate sound propagation through inhomogeneous and moving atmospheres. The tool is benchmarked against established tools from leading research institutions, demonstrating its ability to generate realistic auralizations. Next, the auralized sounds of single aircraft flyover events are evaluated using objective sound quality metrics able to reflect human perception in a quantitative and reproducible way. Such metrics are usually based on sophisticated auditory models, thus being considerably more complex to calculate than conventional metrics based on the sound pressure level. To overcome the lack of accessible and verified implementations, the Sound Quality Analysis Toolbox (SQAT) is developed. An extensive documentation of the toolbox is provided along with verification studies evidencing the reliability and limitations of the implementations. Finally, the framework is applied to study the sound qualities of single aircraft flyover events of a hybrid-wing-body aircraft, in comparison with a conventional tube-and-wing aircraft. Furthermore, auralizations considering different atmospheric conditions are performed to investigate the influence of weather variability on the analysis.