The importance of boundary layer contributions to aircraft cabin noise
levels implies a need for a simple model capable of providing suffici
ent physical insight to address the problem at the design stage. This
paper describes the initial form of such a model, which is based on th
e sound radiated by a single, flat, elastic plate under boundary layer
excitation. A numerical study of the model is presented, the main con
clusions of which are that, for bare cabin walls, increasing the struc
tural damping and decreasing the skin stiffness and number of reinforc
ements will reduce the radiated sound. High excitation levels, due to
matching between the boundary layer and elastic wave velocities, are d
ifficult to avoid, but the effect is not overly sensitive to small var
iations in cruising speed or structural parameters. (C) 1996 Academic
Press Limited