Sound Radiation Characteristics of Underwater Cylindrical Shells with Structural Complexities

In this paper, vibration and sound radiation behaviors of underwater cylindrical shells have been analyzed. Results on modal shapes and radiation efficiency of cylinders' sound radiation modes have been used to comprehend sound radiation characteristics of coupled cylindrical structures. It is found that an effective radiator can be identified by examining whether the vibration pattern is in correspondence with a sound radiation mode with a great radiation efficiency. The sound-structure interactions have been studied through the formulation of radiation reactance matrix. By examining the distribution of reactance force applied on cylindrical surfaces, the changes of resonant frequency in-vacuo and underwater have been discussed. It is found that the similarity between reactance force distribution and vibration distribution determines the modal added mass.