| As a kind of clean renewable energy,wind energy is more and more popular.Therefore,the technology of wind power generation has developed rapidly in recent years.Gradually,wind power generation on land and near shore can no longer meet the needs of human beings,and it has become an inevitable trend of wind power development towards the deep seas.It has become an important practical problem to seek and design an offshore floating platform with good hydrodynamic performance for wind turbines.For the barge type floating platform with the advantages of low cost,simple structure and reliability,the use of bottom opening air cushion improves its hydrodynamic performance.In this paper,an air cushion barge type floating wind turbine platform is proposed and designed for carrying 5MW wind turbine designed and developed by NREL.However,due to the gas-liquid coupling on the free surface inside the air cushion,how the air inside the air cushion affects the performance of the structure has become a major difficulty in the performance research of the air cushion barge.In order to solve this problem,Firstly,the physical conditions inside the air cushion are scientifically simplified that the pressure distribution on the free liquid surface inside the air cushion is assumed to be uniform;Secondly,based on the potential flow theory and linear aerodynamics,the air velocity potential under various modes inside the air cushion is derived by the mathematical method of separating variables from the frequency-domain motion equation;Thirdly,the the parameter of internal aerodynamic coefficient is introduced,the air motion equation based on air velocity potential is constructed,and the calculation formula of aerodynamic coefficient is obtained.Then the calculation method of direct calculation through mathematical derivation and numerical calculation in MATLAB is obtained,and the aerodynamic coefficient of air cushion barge type floating wind turbine platform under the specific design parameters is obtained by the calculation method.Finally,based on the above research content,this paper obtains the mathematical method to solve the motion equation of the floating platform under the gas-liquid coupling by adding the hydrodynamic coefficient matrix and the aerodynamic coefficient matrix.The calculation results obtained by this method are compared with the relevant experimental results,so that the research content is verified.After the above research work,the hydrodynamic response of the floating platform is calculated based on the panel method by using the hydrodynamic performance analysis software wamit,and the dimensionless Rao of the floating platform under various motion modes under regular waves is obtained and compared with the corresponding two solid floating bodies,and the different working water depth and different air cushion volume are analyzed for the floating wind force of the air cushion barge The influence of the hydrodynamic performance of the machine platform.Through the research of this paper,it can be found that the application of air cushion structure in the barge type offshore floating platform can significantly suppress the motion response in the heave direction of the floating platform,and the motion amplitude response in the resonance frequency in the roll and pitch direction can also be effectively suppressed.With the increase of the volume of air in the air cushion,the inhibition effect is more obvious.Finally,the air cushion structure has no obvious inhibition effect on the motion response of the floating platform in surge and sway directions,and in some cases,it will increase the motion response in this direction.The research results of this paper have certain practical significance for the development of offshore wind power industry in China... |
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