Research On Vibration And Acoustic Radiation Of The Submarine

In this dissertation, the numerical computation for the acoustic radiation problem(ARP) is studied deeply and systematically in the theory, method and the application technique, based on analyzing the phylogeny and situation of the home and abroad on the numerical computation for the acoustic radiation problem. The calculating formulas of the boundary element method(BEM) for the exterior acoustic radiation problem in the full-space and half-space are deduced, based on the wave propagation theories. The arising of the non-unique solutions, which is associated with the application of the boundary integral equation(BIE) in acoustic radiation problem is analyzed. The Combined Helmholtz Integral Equation Formulation(CHIEF) is proved to be a effectual and reliable method that can overcome the non-uniqueness problem. The numerical analyses of vibration and acoustic radiation from single-shell submarine is carried out by using FEM software ANSYS and BEM software SYSNOISE. First, the coupled-vibration of the shell and water is calculated and the displacement of the nodes is obtained. Then, by transferring the mesh of the single-shell and the displacement values on the nodes into software SYSNOISE, the sound pressure,the radiated sound power and the radiant efficiency are carried out by SYSNOISE. The characteristics of vibration and acoustic radiation from single-shell submarine is analyzed. The results can reflect the relationship between the sound pressure and the stimulating force. The relationship between the structural damp and the average square velocity is analyzed. The characteristics of the radiation efficiency is carried out. The research work in this paper is valuable for investigation of the vibration and acoustic radiation of the submarine. The conclusion of the paper can be use to predict the acoustic radiation of the submarine and reduce the sound pressure.