The Research On Flow-induced Vibration And Noise Characteristics Of Submarine Fairwater Model

This thesis mainly concerns with the reason for flow-induced vibration of submarine fairwater model. The model adopted in this thesis is one with small fairwater, the characteristics of its outer flow field have been calculated and the research on its vibration and sound radiation characteristics has been done.Firstly, the steady viscous flow field around fairwater model is solved with standard k-εtwo-equation turbulent model by using CFD (Computational Fluid Dynamic) function supplied by FEM (Finite Element Method) software ANSYS. The transition and turbulence are simulated, and then the spatial distribution characteristics of time-averaged physical quantities of the flow field around fairwater model are obtained. When an attack angle exists, the spatial distribution characteristics of flow field time-averaged physical quantities are analyzed. Secondly, by utilizing BEM (Boundary Element Method) software SYSNOISE, the mode of the fairwater are calculated in three cases with the finite element structure model, direct boundary element coupled node model, finite element structure model and indirect boundary element model respectively. The effect of structure vibration characteristics due to water medium is also analyzed. Finally, the radiated sound power of fairwater excited by symmetric forces on transition point is calculated by the application of those models. In contrast with the sound radiation power of different excitation position on fairwater, the sound radiation characteristics of different excitation position on fairwater structure are obtained.This thesis not only calculates the outer flow field of the fairwater, but also calculates the structure vibration and sound radiation characteristics of the fairwater. The results are useful for the submarine fairwater noise control.