Influence of Immersion Depth on the Sound and Vibration Characteristics of the Line Spectrum of a Partially Immersed Model

Herein, the influence of submersion depth on the vibration and sound radiation line spectra of underwater vehicles is investigated. In addition, a partially submerged cylindrical shell was analyzed by the finite element method, and the radiated sound power and root mean square velocity curves of the partially submerged cylindrical shell were obtained. For the partial immersion model, when the immersion depth is large, the load difference between the upper and lower parts of the model is small, whereas when the immersion depth is small, the load difference between the upper and lower parts of the model is large, leading to distortion of the vibration distribution of the model with a small immersion depth, and the vibration of the model is asymmetrical, thus causing the line spectrum of the model to shift to a lower frequency. The vibration distortion of the model also caused the vibration of the model to change from a modal vibration to a nonmodal vibration, resulting in disappearance of the line spectrum of the model. For fully submerged structures, changes in the depth of immersion had little influence on the line spectrum of the structure.