Dynamic Investigations between Two- and Three-bladed Wind Turbines with Various Yaw, Tilt and Cone Angles

Abstract

Tilt and cone are included in wind turbine design to increase tower clearance. Yaw misalignments take place often during turbine operation. The combined effects of these parameters modify the relative wind speed experienced by wind turbine blades, thereby altering the turbine’s dynamics. Consequently, power and loads, key design considerations, are affected. In the absence of exhaustive research available on this topic, this paper provides a quantitative analysis on the impact of tilt, cone and yaw on power and loads. The DTU 10MW Reference Wind Turbine and its two-bladed equivalent are evaluated. The results are obtained using the aeroelastic code HAWC2. It is demonstrated that the ultimate and fatigue loads are greater in the two-bladed than in the three-bladed model during operations. Tilt, cone and ±10º yaw reduce the annual energy production by up to 1%. These three parameters generally increase ultimate and fatigue loads. However, the relationship between these parameters and their impact on the bending moments of both wind turbines is complex, and the results are configuration dependent. It is concluded that the combination of these three parameters must be included as part of the design load examination of any target wind turbine.