Study On Interaction Between Internal Solitary Waves And Submerged Bodies Using Numerical Model

The internal solitary wave is a common form of seawater movements.The interaction between solitary waves and submerged bodies is an important issue in marine engineering and national defense construction.Understanding of the characteristics and the mechanism of the interaction between solitary waves and submerged bodies is essential for the design,manufacture and operation of submerged bodies.In this thesis,the interaction between internal solitary waves and submerged bodies is studied systematically using numerical model.Firstly,based on the Reynolds average Navier-Stokes equation(RANS)and the internal solitary wave theory,a two-dimensional numerical solitary wave channel is established.The interface is captured using the fluid volume method(VOF).The wave is generated using the double push plate method and the dynamic mesh technique.Several typical cases are selected to test the performance of the numerical wave channel and the fluid-solid coupling algorithm.The numerical results are in good agreement with the analytical solutions and experimental data.Secondly,according to the results of series scenarios,the influence of surface boundary conditions,positions of submerged bodies,amplitudes of solitary waves and horizontal scales of the body on the interaction between solitary waves and fixed submerged bodies are analyzed.The results show that under normal conditions,the surface boundary conditions have little influence on the hydrodynamic characteristics of the fixed submerged body.Positions of the bodies,solitary wave amplitudes and horizontal scales of submerged bodies have great influence on the hydrodynamic characteristics of submerged bodies.The force acting on the submerged body near the interface changes severely.The vertical force acting on the submerged body is mainly caused by the density difference(i.e.buoyancy).The larger the horizontal size of the submerged body,the larger the magnitude of the force will be.Then,the interaction between the internal solitary wave and the no-speed floating submerged body are analyzed.The results show that the floating submerged body will sink and rotate rapidly in a short time under the action of solitary waves,and Positions of the bodies,solitary wave amplitudes have great influence on the motion response of submerged bodies.In addition,due to the rotation of the submerged body,the upstream surface becomes larger,and the horizontal force of the no-speed floating submerged body increases significantly.Finally,the interaction between the internal solitary wave and the sailing submerged body is discussed.The results show that the horizontal force of the sailing body is larger than that of the no-speed,and the difference between them is basically constant.The maximum of the negative vertical force is smaller than that of the no-speed.The moment of the sailing body is much larger than that of the no-speed.The speed has little influence on the hydrodynamic trend of the fixed submerged body.At the same time,as the relative speed becomes larger,the time when the submerged body is affected by the internal solitary wave become shorter,and the hydrodynamic change of the submerged body will be more severe.The sailing submerged body will rise and rotate rapidly under the action of solitary waves in a very short time,and the force of the submerged body will be much larger than that of the no-speed.