Fifth International Congress on Sound and Vibration

There is a broad class of active control problems involving control of the acoustic power radiated from a vibrating structure. For many of these applications, it is desirable to implement the control using structural sensors, as opposed to far-field pressure sensors. It is known that the acoustic radiation corresponds to the supersonic wavenumber components of the vibration. Previous work by the authors has demonstrated that one can design distributed sensors that provide a direct measurement of the radiated power using a spatial Fourier transform of the sensor measurements. The sensors have been much more effective in predicting the radiated power than using a similar number of point sensors on the structure. The work reported here uses this wavenurnber information as the basis for an active control system that attenuates the far-field radiation by means of minimizing the supersonic wavenurnber components. The numerical results presented compare and contrast the fro-field results obtained using this active control approach with results obtained when simply minimizing the vibration signal at the discrete locations. The results indicate that significant far-field control can be achieved by directly measuring the supersonic wavenurnber vibration and minimizing that vibration, while ignoring the non-radiating subsonic wavenurnber components.