Numerical Study Of Internal Solitary Wave Propagation On Slope And Its Interaction With Submerged Body

Because of its huge energy and strong shear flow,internal waves will have serious effects on structures such as underwater submersibles,offshore platforms,and underwater pipelines.In order to better guarantee the safe operation of structures such as submerged bodies,it is of great significance to understand the propagation and evolution mechanism of internal solitary waves and the mechanism of interaction with submerged bodies.Based on the Navier-Stokes equations and extended-korteweg-devries theory,this paper constructs a two-layer fluid two-dimensional internal solitary wave numerical flume by using the open source program OpenFOAM for numerical simulation.The velocity inlet method and the gravity collapse method are compared with the laboratory results,and it is found that both of them can fit well,but the waveform generated by the velocity inlet method is more stable and easier to control the wave amplitude.Based on the above research,a real-scale internal solitary wave numerical flume was constructed,the propagation and evolution of internal solitary waves on trapezoidal slope terrain were simulated,and the changes of internal solitary wave surface and flow field under different wave amplitudes and slope terrain heights were analyzed.When the dimensionless amplitude η*≤0.3,the interaction between the trapezoidal slope terrain and the internal solitary wave is weak,and the propagation of the internal solitary wave is basically not affected by the terrain;When 0.3<η*<0.6,the internal solitary wave is obviously deformed during propagation and broken at the top of the slope;When η*≥0.6,the internal solitary wave propagates directly to the rear of the upper slope and breaks directly,and the fragmentation position will move to the front of the slope with the increase of the strength of the interaction between the internal solitary wave and the terrain.The vorticity field is dominated by negative vortices before the breakup of the internal solitary wave.After the breakup,the waveform is reversed,and the flow field becomes dominated by positive vortices.In the subsequent propagation process,the negative vortices gradually disappear.The turbulent kinetic energy reaches the maximum in the wave breaking area,and then the wave gradually stabilizes and begins to decrease as the wave breaks.Finally,the interaction between the internal solitary wave and the submerged body is preliminarily discussed,and the influence of the submerged body on the flow field and the force change of the submerged body with or without terrain are analyzed.The results show that the maximum dimensionless horizontal force increases first and then decreases with the increase of the slope height.When the dimensionless amplitude η*<0.4,the maximum dimensionless horizontal force increases with the increase of the slope height.When the dimensionless amplitude η*>0.4,the maximum dimensionless horizontal force decreases with the increase of the slope height.The existence of the trapezoidal slope terrain will reduce the force of the internal solitary wave on the submerged body,but with the increase of the slope terrain height,the interaction between the terrain and the internal solitary wave will further strengthen,and the slope terrain will affect the internal solitary wave on the submerged body.The magnitude of the weakening of the force gradually decreases.