Study of the influence of added water and contained water on structural vibrations and acoustic radiation using different dynamic modeling methods

Using the 3-D sono-elasticity method and the simplified nonstructural mass method, the different dynamic modeling methods of the added water for a single-hull structure are first analyzed in this study. Then, the complete internal flow field method and the simplified nonstructural mass method of the contained water between the double hulls of a double-hull structure are investigated. Finally, based on the calculation and analysis under multiple conditions, a reasonable and simplified dynamic modeling method of added water and contained water is obtained. It is indicated that the mass of added water for a single-hull structure is closely related to the mass of total underwater displacement of the structure. With the increase in the analysis frequency, the mass of added water is characterized by first decreasing rapidly and then decreasing gradually and smoothly. The contained water between the double hulls is distributed to the pressure hull and the light shell based on the ratio of the impedances of the double hulls. The results can basically reflect the acoustic radiation characteristics of the double-hull structure.