Turbulence influence on offshore wind turbines implementation

Abstract

Turbulence of the atmospheric flow in the boundary layer depends on different factors, such as: the roughness of the ground, the orography, the sea surface state and atmospheric stability conditions. In open sea conditions, the transfer of momentum from the atmosphere to the ocean is very important, since part of it contributes to the generation of waves, while the rest influences the turbulence and currents convective generation. In the offshore wind turbines wakes, the level of turbulence is greater than the wind without obstacles, causing transient loads to occur in other wind turbines located downstream, which has a structural stress effect on its components. Another effect of the wakes is the lack of uniformity of the vertical flows of the wind, that is to say, of shear, thereby increasing cyclic loads on wind turbine rotors. Therefore, in the of offshore wind farms implementation it is necessary to evaluate the turbulence in the site, since this will generate dynamic structural loads on the wind turbines, as well as variations of their electrical production.