Wave-resolving aircraft cabin noise prediction

Quiet aircraft passenger cabins contribute significantly to the well-being and health of billions of air travellers. During design, a reliable prediction of the sound pressure level is seen as crucial decision-making basis.The wave-resolving numerical simulation of sound pressure levels in the cabin is investigated within this thesis, which results in a comprehensive modelling of a typical aircraft fuselage, the efficient numerical solution and the assessment of the sound induced by a novel engine concept and the turbulent boundary layer.A major challenge is the complexity of aircraft models including structural, acoustic and poro-elastic domains. For each relevant fuselage part, experiments are conducted and different vibroacoustic models are compared in order to choose a suitable modelling approach, repectively. As the resulting finite element model incorporates millions of degrees of freedom, efficient solving approaches are studied with regard to potentially introduced errors. The aircraft fuselage model in combination with efficient solving approaches is applied for two analyses. Firstly, the available acoustic excitations of two jet engines are compared.Secondly, the acoustic excitations beneath the turbulent boundary layer are modelled by a generic superposition of plane waves resulting in a deterministic snapshot of the random loading. It is demonstrated that the turbulent boundary layer generates cabin sound pressure levels lying between those of the two engine generations. The obtained results represent a decisive contribution towards the development of quieter passenger cabins in future aircraft.