Abstract:
A significant component of the interior noise of aircraft and automobiles is a result of the turbulent boundary layer excitation of the vehicular structure. In this investigation the feasibility of active control of wind noise is studied. Initial studies are made by considering the idealized case of sound radiation from a simply supported panel excited by a turbulent flow boundary layer. To study various control system alternatives, a wind noise model is developed. The model consists of a modal model of the excitation of a plate from a turbulent boundary layer, a model of plate vibrations, and a model of the sound radiated from the plate. A frequency-domain approach, similar to quantitative feedback theory, is utilized in the design of a robust feedback controller. The controller utilizes plate acceleration feedback while maintaining sound-pressure-level reduction as the primary design objective. The design method insures that performance and control effort objectives are met for plant and disturbance uncertainty. The controller design method offers flexibility in configuring the size of the controller, and the effect of the performance and control effort objectives on the controller design are easily identified.