Dynamic Response Analysis Of Offshore Wind Turbine Under Wind Wave Current Coupling

As a kind of clean energy,wind energy is attracting people's attention.Compared with land wind power,offshore wind power has the advantages of low turbulence intensity,stable wind direction and small friction.However,the marine environment is complex,wind turbines are prone to vibration deformation,structural fatigue,damage and even collapse.As the best carrier of wind energy development and utilization,it is an important content of our research to ensure the safety and stability of offshore wind turbine structure under different load conditions.In this paper,the 5MW wind turbine is taken as the research object.Through the modal analysis of the wind turbine tower to prevent its resonance,and then through the two-dimensional flume to simulate the environment under the wind wave current coupling,the dynamic response analysis of the wind turbine is carried out by the method of fluid structure coupling.Using Solidworks to build the model of each part of the offshore wind turbine and assemble the whole machine.Before studying the dynamic response of wind turbine under the coupling action of wind,wave and current,the inherent characteristics of the tower,which is an important part of wind turbine,are analyzed firstly.The natural frequency and vibration mode of the tower are obtained.Campbell diagram is drawn and compared with the excitation frequency to determine whether the resonance of wind turbine occurs in the safe operation area.In order to make the simulation results more close to the real sea conditions,a two-dimensional pool is constructed and the secondary development of UDF is carried out by using the fluid flow(fluent)module in the workbench software.The structure of wind,second-order Stokes wave and current coupling environment is realized.The pressure,velocity vector,streamline and other cloud maps of the pool environment are obtained and analyzed.At the same time,the influence of wave motion on wind speed and the formation process of second-order Stokes wave are analyzed.The coupling process of flow field domain and solid domain is established by ANSYS Workbench,and the simulation analysis of wind turbine in wind wave and current environment is realized.The pressure,displacement,equivalent stress and other cloud maps of wind turbine surface are obtained.The results show that the surface pressure of the fan decreases with the increase of the height,and the surface pressure on the front side of the fan is larger than that on the back side.For the structural deformation analysis of the whole machine,the deformation is mainly concentrated in the upper part of the middle section of the tower,and the displacement at the top of the tower is the largest.For the analysis of three blades,the maximum deviation value of the blade is located at the highest point,and the maximum is located at the tip of the blade.In terms of the equivalent stress of the whole machine,the stress extremes of the front and the back are located at the bottom of the tower,and the root stress of the blade is the minimum.According to the surface stress simulation of the wind turbine in the wind wave current coupling environment,the first-order frequency of the wind turbine in the wind wave current coupling environment is far greater than the wave frequency,that is,the wind turbine will not resonate with the wave,in a safe environment,the research and analysis results of this paper have very important theoretical significance and application value.