Noise transmission characteristics of a large scale composite fuselage model

Results from an experimental test undertaken to study the basic noise transmission characteristics of a realistic, built-up composite fuselage model are presented. The floor-equipped stiffened composite cylinder was exposed to a number of different exterior noise source configurations in a large anechoic chamber. These exterior source configurations included two point sources located in the same plane on opposite sides of the cylinder, a single point source and a propeller simulator. The results indicate that the interior source field is affected strongly by exterior noise source phasing. Sidewall treatment is seen to reduce the overall interior sound pressure levels and dampen dominant acoustic resonances so that other acoustic modes can affect interior noise distribution.