Blade Load Reduction for a 13 MW Downwind Pre-Aligned Rotor

Sang Lee, Patrick Moriarty, Chao Qin, Eric Loth

Research output: Contribution to conferencePaperpeer-review

4 Scopus Citations


To alleviate the mass-scaling issues associated with conventional upwind rotors of extreme-scale turbines, a downwind rotor concept is considered that uses coning and downwind curvature to align the non-circumferential loads for a given steady-state condition. This load-alignment can be pre-set to eliminate downwind blade moments for a given steady-state condition at rated wind speed and to minimize them for other conditions. The alleviation in downwind dynamic loads may enable a reduced structural blade mass as compared with a conventional upwind rotor. To examine the potential impact of this design, FAST simulations were conducted for a 13.2 MW rated turbine at steady-state conditions for two rotor configurations with similar power outputs: 1) a conventional upwind rotor with three blades and 2) a downwind pre-aligned rotor with two blades. The rotor mass was reduced by approximately 25% for the downwind pre-aligned configuration. In addition, the damage equivalent loads on the blades were reduced at all wind speed for the downwind pre-aligned configuration, with a reduction of more than 60% at the rated condition.

Original languageAmerican English
StatePublished - 2016
Event34th Wind Energy Symposium, 2016 - San Diego, United States
Duration: 4 Jan 20168 Jan 2016


Conference34th Wind Energy Symposium, 2016
Country/TerritoryUnited States
CitySan Diego

Bibliographical note

Publisher Copyright:
© 2006, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

NREL Publication Number

  • NREL/CP-5000-66044

Other Report Number

  • AIAA 2016-1264


  • alignment
  • coning
  • downwind curvature
  • downwind rotor
  • steady-state condition


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