Study Of The Mechanism Of Upwelling And Wake Induced By A Cone-Truncated Guyot

Guyots are one of the important components of the complex marine landscape,and have significant effects on the biological system,the flow of seawater,climate change and oceanic fisheries.In particular,the flow of seawater is complex near Guyots.Compared with the flat deep-sea topography at the bottom,the interaction between guyots and currents often causes a series of significant changes of the current.The typical phenomena of the flow near Guyots are the upwelling,the vortex shedding and the internal wave.It is of great significance to study the influence of the upwelling,the vortex shedding and the internal wave,and to understand the evolution of the upwelling,the vortex shedding and the internal wave in order to promote the development of marine ecology,military oceanography,marine acoustics and other related disciplines as well as marine traffic,marine production and seafloor development.In the thesis,the flow around a guyot with uniform and linear stratified fluids is studied by three-dimensional numerical simulation,and the influence of the guyot on the flow is quantitatively analyzed.All results are followed:Firstly,the model of a guyot is established based on the sea topography;the turbulence model,grid and time step are tested and the numerical procedures are presented under consideration of accuracy and computing cost;the feasibility of the large eddy simulation turbulence model is conducted in comparison with experimental data.Secondly,the flow around the cone-truncated guyot with uniform inflow is simulated for Re=102?106.The results show that the flow around a guyot is dependent on the Reynolds numbers and the hydrodynamic parameters for the flow around the guyot is quantified.Finally,the flow around the cone-truncated guyot with linear stratification inflow is simulated for different Reynolds numbers and Froude numbers.The results show that the upwelling,separation point,vortex shedding and internal wave are dependent on the Reynolds number and the Froude number;scaling laws of the hydrodynamic parameters are presented.In the thesis,the flow around the guyot with uniform and linear stratification inflow is studied and analyzed in quantity.However,due to the limitation of computing cost and time,the accuracy of numerical simulation can be improved;additionally,the theoretical analysis and experiment are also needed.