Prediction of the Impact of Jet Mixing Noise on a Generic Aircraft Fuselage in Cruise Flight

摘要

Together with the turbulent boundary-layer induced excitation noise and engine fan noise, jet noise is an important aeroacoustical source of aircraft cabin noise. In the framework of the Collaborative Research Center SFB 880 this study prepares the comparison of the impact of jet noise under cruise condition on the fuselage of a generic aircraft between a conventional engine with a bypass ratio (BPR) of 5, mounted below the wing, and an ultra high bypass ratio (UHBR) engine at over the wing position. Therefore CAA (computational aeroacoustics) computations are carried out by means of the DLR CAA solver PIANO combined with the FRPM method to model 3D stochastic sound sources. To capture the fine scale jet noise, the Tarn & Auriault model is involved. The 3D simulations cover the area which is directly affected by the jet up to the fuselage surface, where the refraction effect of the turbulent boundary layer is taken into account. The resulting surface pressure fluctuations on the aircrafts fuselage are sampled with a high temporal and spatial resolution and are finally used as realistic input for a finite elemente (PE) model of the fuselage structure. Additional 2.5D CAA computations for the isolated jet are conducted with the modal formulation of PIANO / RPM to verify the 3D simulations.