Study On Hydrodynamic Characteristics Of Wave Field Coupled With Small Scale Broken Ice And Floating Platform

With the rapid depletion of onshore and offshore oil and gas resources,it is gradually difficult to meet the potential needs of human continued development.Therefore,as an important global oil and gas resource reserve base,polar regions have attracted the attention of all countries in the world.In recent years,due to the continuous effect of greenhouse effect,the range and thickness of polar sea ice are decreasing,further increasing the possibility of the opening of the Arctic route and the exploitation of natural resources.However,the complexity and harshness of the polar environment pose a huge threat to the safety in the process of oil and gas development,followed by higher requirements for the design,manufacture and safe operation of polar marine equipment.As one of the most important offshore oil and gas development equipment,floating platform plays an important role in oil and gas development due to its strong adaptability and adaptability to deepwater operations.However,when the target platform works in the periglacial zone,it will not only suffer from the continuous action of various complex environmental loads such as wind,wave and current,but also suffer from the collision of sea ice.For this reason,based on the idealized assumption of the interaction process between broken ice and marine structures,this thesis has carried out relevant research using the simulation software STAR-CCM+.The main research contents are as follows:First of all,a three-dimensional numerical wave tank is established based on CFD technology to verify the grid independence and time step independence.Stokes fifth order waves with deep water conditions are generated by using the velocity inlet wave making method and the damping wave elimination method.The accuracy of the numerical tank is verified by comparing the numerical waveform with the theoretical waveform,Based on this model,the wave and wave climbing results at different locations around the platform are simulated,and the wave climbing effect around the floating platform is analyzed.Secondly,the broken ice is simplified as a rigid floating body,and the three-dimensional rigid single broken ice movement is simulated by using the overlapping grid technology.A numerical calculation model for the motion response of a single broken ice under the combined action of waves and currents is established.The motion response of broken ice with different section shapes and different scales under the same wave and current loads is studied respectively,and the selected broken ice shape is finally determined through comparative analysis.Finally,using the CFD-DEM coupling numerical calculation method,a cohesive ice model of the interaction between particles is built in the discrete element method,and the numerical simulation of the interaction process between the small and medium-sized broken ice in the wave field and the floating platform is carried out,and the variation law of the ice load on the floating platform under different velocity and density is explored.