Use of acoustic basis functions for active control of sound power radiated from a cylindrical shell

Abstract

In a previous paper by the authors [J. Acoust. Soc. Am. 92, 856–870 (1992)], a general strategy was devised for achieving minimum radiation of sound from structures subjected to a harmonic excitation force. In this strategy, a quadratic expression is written for the total sound power radiated from the structure in terms of the primary and actuator (control) forces. Using quadratic optimization of this expression, a single control force vector is found which minimizes the radiated sound power for the particular acoustic model of the structure. The structural response to this control force is referred to as the “weak radiator” response and is then used as an objective function for an adaptive algorithm. In previous work, this strategy was used to control the sound radiated from a baffled beam. The work presented in this paper extends the application of this strategy to the case of a cylindrical shell with endcaps. Numerical predictions were verified experimentally. These results show that this strategy is successful in controlling the sound radiated from the cylindrical shell by yielding large reductions in the structural supersonic wave number content.