BOUNDARY-LAYER INDUCED NOISE IN AIRCRAFT .1. THE FLAT-PLATE MODEL

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