| An ITTC recommended surface combatant with representative shape is chosen for numeri-cal simulation. The flow field around it and the bow flow noise are calculated for research, which aims to provide a numerical method for estimating performances of sonar dome molded lines. The work includes the following processes: three-dimensional modeling, fluid domain defining, mesh generating, setup of initialization and boundary condition, selecting of physical model and mathematical arithmetic, iterative calculation, analysis of flow field and sound field.Ogrid topology is used to fit the ship's complex hull shape, and pure hexahedral structured grids are created. The ship surface is replaced by a flat panel to calculate the mesh parameters of boundary layer. The precision of total resistance, frictional resistance and pressure resistance is below 2%, and wave profile fits well. The ship's surface static pressure and global wave eleva-tion are logical. To investigate the change of resistance, the value of turbulence quantities at inlet boundary is transferred, and two typical advanced turbulence models are used. Some significant problems are brought forward and discussed personally.Surface acoustic power, turbulent kinetic energy and turbulent intensity around the sonar dome are calculated to analyze noise source distribution, considering the free surface effect. The sound field results match the experimental phenomenon well. Some suggestions are provided for sonar installation and sound pressure signal processing. Furthermore, the intensity of noise source is calculated with different speeds and logical data is gained.The numerical method, used for calculating the flow field and sound field of surface com-batant, is detailedly described. Some useful conclusions are summarized and some creative means are utilized, providing reference for correlative engineers. |
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