Active structural acoustic control of a submerged finite cylindrical shell and its physical mechanism

The active structural acoustic control of a submerged finite cylindrical shell is investigated. Firstly, considering fluid-structure coupling interaction, the analytic expression of the optimal complex intensity of secondary force is derived according to uncoupled characteristic of the sound power radiated from the finite cylindrical shell in the circumferential direction. Secondly, the control effects with single control force and two control forces are compared. Lastly, the physical mechanism of active structural acoustic control of the submerged finite cylindrical shell is analyzed based on the relation of structural vibration mode and acoustic radiation mode. The results show that the more reduction is obtained using multiple secondary forces by control the vibration of the shell which effectively produces the sound radiation; The radiation efficiency of the first several order radiation mode is very high, but with lower mode amplitude, the physical mechanism of active control is to reduce the amplitude of acoustic radiation modes corresponding to structure vibration modes, thus effectively control the sound radiated from structural vibration.