Buffeting response analysis of offshore wind turbines subjected to hurricanes

The objective of this paper is to investigate the effects of newly observed hurricane turbulence models on offshore wind turbines by considering unsteady aerodynamic forces on the tower and wind-wave-soil-structure interaction. The specific goals were analyzing the tower and blade structural buffeting responses, the low cycle fatigue during different hurricane categories, and extreme value of the short term responses. To achieve these goals, first, the recent observations on hurricane turbulence models were discussed. Then a new formulation for addressing unsteady wind forces on the tower was introduced and NREL-FAST package was modified with new formulation. Results showed that recently observed turbulence models resulted in larger structural responses and low cycle fatigue damage than existing models. In addition, extreme value analysis of the short term results showed that the IEC 61400-3 recommendation for wind turbine class I was conservative for designing the tower for wind turbine class S subjected to hurricane; however, for designing the blade, IEC 61400-3 recommendations for class I underestimated the responses.