Prediction of installed jet noise due to swept wings

© 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. An analytical model is developed in this paper to model the sound due to the scattering of instability waves by an aircraft wing with a swept trailing edge. The model is based on the Schwartzchild method and Amiet's approach is used to obtain the far-field sound. The model can correctly predict both the reduction in installed jet noise and the change to directivity patterns observed in experiments due to the use of swept wings. The agreement between the model and experiment is very good, especially for the directivity at large azimuthal angles. It is found that the principle physical mechanism of sound reduction is the destructive interference effect. It is concluded that in order to obtain an effective noise reduction, both the span and the swept angle of the wing have to be large.