Active control of sound transmission and radiation into an enclosure based on acoustic radiation modes

The problem of sensing and active control of sound radiation into an enclosure was studied from the point of view of the acoustic radiation mode using the structural error sensing. First, the physical characteristics of the radiation modes and the inherent relationships between the acoustic modes and the radiation modes were analyzed in detail. A model for the active control of sound radiation from the vibrating structure into an enclosure was presented based on the radiation modes sensing, and a method for obtaining the error signal using the sensor array and designed radiation modes filter was proposed. The numerical simulations and analyses with the proposed strategy were conducted. The influence of the number and location on the error sensing and active control was discussed. The simulation results demonstrate that the coupling between radiation modes and cavity modes is strictly selective; the radiation mode shape is very similar with the projection on the coupling surface of coupled main cavity mode. In general the potential energy of the first three radiation modes needs to be sensed and minimized at the low frequency range to attain the similar control effect to the potential energy minimization (PEM), however at the lower frequencies or near the natural frequencies of the cavity, only the first most efficient radiation mode needs to be minimized to attain the similar effect to the PEM.