Active structural-acoustic control (ASAC) has been demonstrated in the literature for several elementary structures using analytical models of the dynamic response. However, analytical approaches cannot be used for the practically important case of a 3-dimensional structure immersed in a dense fluid, which occurs primarily in marine applications. Such fully coupled problems, in which appreciable fluid-structure interaction takes place, require a numerical approach. This paper outlines efforts to study ASAC by computing dynamic responses of the structure/fluid system with the computer program NASHUA. Two separate feed-forward control algorithms are developed and compared: a spatial-domain algorithm based on minimizing the radiated power, and a wavenumber-domain algorithm that does not require farfield pressure information. A spherical shell is examined to provide insight to the mechanisms by which ASAC reduces low-frequency radiation, and the results are compared with a closed-form solution.
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