The Surface Wake Generated By A Submerged Moving Body In A Stratified Viscous Fluid And Its Interaction With The Stochastic Ocean Waves

Density stratification is a common occurrence in the ocean owning to the variation of water temperature and salinity with depth. When the submarine travels in the stratified fluids, not only the vortices and the wakes of turbulence, but also the wakes of internal waves will be generated. The internal waves can propagate along the level direction and the perpendicularity one. In the process of propagation, the wakes will induce the slight variation of the flow velocity and displacement fields on the ocean surface, and then the coarseness characteristics of the ocean surface will be changed with the interaction of the stochastic ocean waves, thus these characteristics can be detected by SAR (Synthetic Aperture Radar). However, so for, the knowledge of the related mechanism is still very limited. Therefore, this thesis is of importance for the non-sound detection of submarines.Firstly, the unsteady viscous numerical method based on 3-D incompressible RANS equations, RNG k ?εturbulence model and VOF method are used to simulate the wake characteristics of a submerged sphere moving in a stratified fluid. With the ocean wave spectrum model, the behaviours of the interaction between the free-surface wakes generated by a submerged moving sphere and the stochastic ocean waves are numerically analyzed for various wind velocities and various significant wave heights.On the basis of these works, the wake characteristics of a submarine with various appendages moving in a stratified fluid are also simulated successfully by using a...