Acoustic radiation from cylindrical shells due to internal forcing

Abstract

This paper studies sound radiation from cylindrical shells due to internal sources; the sources excite structural vibrations inside the shell, which are transmitted to the shell through structural coupling between the shell and its internals, and then partially radiated from the shell into the acoustic medium as sound. The internal structure is represented by an elastic plate attached to the shell along its axial direction, modeling decks in real underwater vehicles. A standard method for solving such coupled problems is used to derive solutions in terms of receptances of the shell and the plate, which relate the responses of the two to coupling forces and bending moments at the connections between them. The forces and moments are then determined by kinematic and dynamic balances between the shell and the internal plate. Far-field solutions are examined in detail to identify dominant features in the radiation process, such as those controlling the frequency characteristics and the directivity pattern of the radiated field.