Prediction of the radiated sound power from a fluid-loaded finite cylinder using the surface contribution method

Based on acoustic radiation modes, the surface contribution method has been developed to predict the surface contributions to the radiated sound power from a vibrating structure. In this work, the surface contribution method is used to identify the sound field on a vibrating structure submerged in a heavy fluid. It was recently found that surface contribution method was not able to predict the surface contributions at low frequencies when the structural wavenumber is higher than the acoustic wavenumber. In this paper, the acoustic radiation efficiencies calculated for different numbers of integration points are compared and used to compute the surface contributions to the radiated sound power. The radiated sound power obtained from both the surface contribution and the active intensity methods are compared. Numerical results for a fully coupled finite element/boundary element model of a cylindrical shell with hemispherical end closures submerged in water show that the surface contribution method can also be successfully applied at low frequencies.