Abstract

Internal solitary waves (ISW) often appear in the actual ocean and carry huge energy. In order to study the interaction between the ISW and the underwater objects, considering the variation law of the fluid density along the depth direction in the actual ocean, the numerical calculation model for the ISW and the submarine in the stratified fluid is established based on the Korteweg de Vres (KdV) theory and the RANS method. The load characteristics of the ISW on the submarine are studied by using the overset mesh technology and the method. When the submarine passes through the ISW, the change of its buoyancy will cause a sharp change in the vertical load. The ISW-induced flow field will also affect the force on the submarine. The ISW-induced forces increase with the increase of the ISW amplitudes. When the submarine is completely below the peak of the waveform, the load is mainly affected by the flow field structure; the force amplitude is small, and the impact of the submergence depth is small. 

Abstract

Internal solitary wave is an important nonlinear fluctuation phenomenon in the ocean, which carries huge energy in the propagation process and poses a great threat to the safety of underwater navigation bodies. In order to study the motion characteristics of submarines under internal solitary waves, this paper establishes an internal solitary wave model based on the mKdV theory, and proposes an overall flow field domain grid model displacement method by encrypting the local grids and applying the overlapping grid technology, which does not need to consider the numerical errors generated by the traditional wave-making technology, and realizes the assessment of the impact of isolated waves in the large-scale spatial and temporal domains, and has the characteristics of small computation, high success rate, simple wave-making, easy data collection and high economy. It is characterized by small calculation volume, high success rate, easy data collection and high economy. The study shows that the submarine under the action of internal solitary wave will produce a large dive movement, and after crossing the center of the valley of the internal solitary wave, it will do the uplift movement with the wave surface of the internal solitary wave against the wave.