Aircraft manufacturers are constantly striving to improve passenger comfort and one area that has always been particularly associated with this is the level of external noise audible in aircraft cabins. Boeing has traditionally achieved this by increasing aircraft soundproofing, which, in turn, often introduces weight and makes aircraft more inefficient. Until now...
One of Boeing’s UK suppliers, QinetiQ, has been working with computer models to predict civil aircraft interior noise levels in response to external aerodynamic sources of sound, with a focus initially on the 787 family. The novel materials and construction of the 787 fuselage provide new challenges and opportunities for the noise control engineer and the results will allow Boeing to construct not only a quiet passenger environment but one that is lighter and ultimately more environmentally efficient. The sources to be considered include pressure fluctuations in the turbulent boundary layer (TBL) flow over the aircraft skin and acoustic sources associated with the outflow from the engines, including jet-mixing noise and "shock-cell" noise.
Flight and wind-tunnel tests are not only more time-consuming, but are expensive and difficult. In this context, therefore, there is an even greater need for reliable computer models, validated against genuine acoustic measurements.
The outputs from the model will provide input into Boeing’s full vibro-acoustic model of the aircraft providing a comprehensive and world-leading predictive tool for aircraft interior noise.