Aerodynamic Characteristics Of Large Vertical Axis Wind Turbines And Hydrodynamic Characteristics Of Floating Foundation

Offshore floating wind turbine system is an important direction for the development and utilization of new energy.Compared with the horizontal axis wind turbine,the vertical axis wind turbine has no complex yaw for the wind system,the power generation equipment is located at the bottom of the tower,the manufacturing process is simple,the operation and maintenance is convenient,and the noise pollution is small,and so on.Taking the large vertical axis wind turbine and its semi-submersible floating foundation as the research object,the shear effect of air flow is considered,and the wind speed profile of the marine environment is the inlet boundary condition of the wind tunnel,considering the shear effect of the atmospheric environment,providing the wind profile of the marine environment as the tunnel entrance boundary conditions,based on STAR-CCM+ software platform,CFD method is used to study the aerodynamic characteristics of 5MW vertical axis wind turbine.The difference between the shear flow and the uniform flow is analyzed by the power coefficient,the tangential force coefficient,the normal force coefficient and the pressure coefficient of the blade surface;for a wind turbine model with or without a tower cylinder,tower shadow effect on the large vertical axis wind turbine power generation was investigated thoroughly;and by changing the tower diameter,the influence of the size of the tower column on the tower shadow effect is studied with the torque coefficient,the variation of the wind pressure distribution on the blade surface and the structure of the velocity vortex structure.Based on the potential flow theory and ANSYS/AQWA platform,taking Deep CWind semi-submersible foundation as the research object,the upper vertical axis wind turbines are in the shut-down condition,the surge and pitch motions were discussed by changing the incident angles and the cable length,the variation of cable tension and horizontal cable length were analysed from the points of view of mooring stiffness and mooring force,applying periodic external torque loads on the floating semi-submersible foundation,to research the influence of external torque on the motion of surging,pitching and yawing of semi-submersible floating foundation.