Document Type : Research Article


1 Department of Mechanical Engineering, Shahrood University of Technology, P. O. Box: 3619995161-316, Shahrood, Semnan, Iran.

2 Fars Power Generation Management Company, Shiraz, Fars, Iran.

3 Department of Mechanical Engineering of Biosystem, Shahrood University of Technology, P. O. Box: 3619995161-316, Shahrood, Semnan, Iran.



Significant growth of the wind power market has led to a dramatic increase in the scale and capacity of wind turbines over the past decades. As these extreme-scale structures are expected to pose a wide range of challenges, an innovative concept which both lightens blade's mass and improves their aerodynamic performance, is vital for the future of rotor's design. In the present study, modeling and evaluating of an innovative pre-aligned rotor design based on SANDIA SNL100-00 wind turbine blade were accomplished. To evaluate the aerodynamic performance of the proposed rotor, CFD simulation was used as a well-developed technique in fluid mechanic. In the new rotor design, the swept area was increased using an equal blade length and the blade sections were more appropriately aligned with the wind flow compared to the reference model. This enhancement attained due to transferring the bending position from the root to a certain point alongside the length of blade. According to simulation assessments, this modification led to the overall improvement of main performance parameters in terms of the mean power and the applied torque on the blades. The simulation revealed that the novel concept is capable of increasing the mean power coefficient by 13.21 % compared to the conventional rotor designs. Analysis of the axial induction in front of the rotor plane displayed a greater drop in the flow velocity streaming up to the rotor, which could lead to have a more efficient configuration for harnessing the upcoming wind's power.


Main Subjects

  1. Loth, E., Steele, A., Qin, C., Ichter, B., Selig, M.S. and Moriarty, P., "Downwind pre‐aligned rotors for extreme‐scale wind turbines", Wind Energy, Vol. 20, No. 7, (2017), 1241-1259. (
  2. Wingerden, J.V., Hulskamp, A., Barlas, T.K., Marrant, B., Kuik, G.V., Molenaar, D.P. and Verhaegen, M., "On the proof of concept of a smart wind turbine rotor blade for load alleviation", Wind Energy, Vol. 11, (2008), 265-280. (
  3. Chetan, M., Sakib, M.S., Griffith, D.T. and Yao, S., "Aero-structural design study of extreme-scale segmented ultralight morphing rotor blades", Proceedings of AIAA AVIATION 2019 Forum, Dallas, Texas, (2019). (
  4. Fischer, G.R., Kipouros, T. and Savill, A.M., "Multi-objective optimisation of horizontal axis wind turbine structure and energy production using aerofoil and blade properties as design variables", Renewable Energy, Vol. 62, (2014), 506-515. (
  5. Sartori, L., Bellini, F., Croce, A. and Bottasso, C., "Preliminary design and optimization of a 20 MW reference wind turbine", Journal of Physics: Conference Series, Vol. 1037, (2018). (
  6. Griffith, D.T. and Richards, P.W., "The SNL100-03 blade: Design studies with flatback airfoils for the Sandia 100-meter blade", Sandia National Labs, Technical report SAND2014-18129, (2014). (
  7. Deshmukh, A.P. and Allison, J.T., "Multidisciplinary dynamic optimization of horizontal axis wind turbine design", Structural and Multidisciplinary Optimization, Vol. 53, (2016), 15-27. (
  8. Fingersh, L.J., Hand, M.M. and Laxson, A.S., "Wind turbine design cost and scaling model", National Renewable Energy Lab (NREL), Golden, Colorado, USA, (2006). (
  9. Loth, E., Steele, A., Ichter, B., Selig, M. and Moriarty, P., "Segmented ultralight pre-aligned rotor for extreme-scale wind turbines", Proceedings of AIAA Aerospace Sciences Meeting, Nashville, Tennessee, USA, (2012). (
  10. Thomsen, O.T., "Sandwich materials for wind turbine blades - Present and future", Journal of Sandwich Structures & Materials, Vol. 11, (2009), 7-24. (
  11. Thirumalai, R. and Prabhakaran, D., "Future materials for wind turbine blades - A critical review", Proceedings of International Conference on Wind Energy: Materials, Engineering and Policies, Hyderabad, India, (2012). (
  12. Konga, C., Banga, J. and Sugiyamab, Y., "Structural investigation of composite wind turbine blade considering various load cases and fatigue life", Energy, Vol. 30, (2005), 2101-2114. (
  13. Liao, C.C., Zhao, X.L. and Xu, J.Z., "Blade layers optimization of wind turbines using FAST and improved PISO algorithm", Renewable Energy, Vol. 42, (2012), 227-233. (
  14. Rasmussen, F., Petersen, J.T., Vølund, P., Leconte, P., Szechenyi, E. and Westergaard, C., "Soft rotor design for flexible turbines- Final report", (1998), 1-19. (
  15. Tong, W., Wind power generation and wind turbine design, WIT Press, (2010). (
  16. Loth, E., Selig, M. and Moriarty, P., "Morphing segmented wind turbine concept", Proceedings of 28th AIAA Applied Aerodynamics Conference, Chicago, Illinois, USA, (2010). (
  17. Daynes, S. and Weaver, P.M., "Design and testing of a deformable wind turbine blade control surface", Smart Materials and Structures, Vol. 21, No. 10, (2012). (
  18. Neal, D.A., Good, M.G. and Johnston, C.O., "Design and wind-tunnel analysis of a fully adaptive aircraft configuration", Proceedings of 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics & Materials Conference, Palm Springs, California, USA, (2004). (
  19. Buhl, T., Bak, D.C., Gaunaa, M. and Andersen, P.B., "Load alleviation through adaptive trailing edge control surfaces: Adapwing overview", Proceedings of European Wind Energy Conference and Exhibition, Milan, Italy, (2007). (
  20. Lachenal, X., Daynes, S. and Weaver, P.M., "Review of morphing concepts and materials for wind turbine blade applications", Wind Energy, Vol. 16, (2013), 283-307. (
  21. Wang, W., Caro, S.E. and Bennis, F., "Optimal design of a simplified morphing blade for fixed-speed horizontal axis wind turbines", Proceedings of the ASME 2012 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, Chicago, Illinois, USA, (2012), 233-242. (
  22. Lackner, M.A. and Kuik, G.V., "A comparison of smart rotor control approaches using trailing edge flaps and individual pitch control", Wind Energy, Vol. 13, (2010), 117-134. (
  23. Griffith, D.T., "Structural design of the SUMR-13 wind turbine blade- Technical report M2.5.9", Advanced Research Projects Agency - Energy, (2017). (
  24. Steele, A., Ichter, B., Qin, C., Loth, E., Selig, M. and Moriarty, P., "Aerodynamics of an ultralight load-aligned rotor for extreme-scale wind turbines", Proceedings of 51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, Grapevine, Texas, USA, (2013). (
  25. Yao, S., Chetan, M. and Griffith, D.T., "Structural design and optimization of a series of 13.2  MW downwind rotors", Wind Engineering, Vol. 45, No. 6, (2021), 1459-1478. (
  26. Ananda, G.K., Bansal, S. and Selig, M.S., "Aerodynamic design of the 13.2 MW SUMR-13i wind turbine rotor", Proceedings of Wind Energy Symposium, American Institute of Aeronautics and Astronautics, Kissimmee, Florida, USA, (2018). (
  27. Noyes, C., Qin, C. and Loth, E., "Pre-aligned downwind rotor for a 13.2 MW wind turbine", Renewable Energy, (2018), 749-754. (
  28. Zalkind, D.S., Ananda, G.K. and Chetan, M., "System-level design studies for large rotors", Wind Energy Science, Vol. 4, (2019), 595-618. (
  29. Noyes, C., Qin, C. and Loth, E., "Ultralight morphing rotor for extreme-scale wind turbines", Proceedings of AIAA SciTech Forum, (2017), 1-6. (
  30. Ichter, B., Steele, A., Loth, E., Moriarty, P. and Selig, M., "A morphing downwind‐aligned rotor concept based on a 13 MW wind turbine", Wind Energy, Vol. 19, (2016), 625-637. (
  31. Noyes, C., Qin, C. and Loth, E., "Analytic analysis of load alignment for coning extreme-scale rotors", Wind Energy, Vol. 23, (2020), 357-369. (
  32. Qin, C., Loth, E., Zalkind, D.S., Pao, L.Y., Yao, S., Griffith, D.T., Selig, M.S. and Damiani, M.S., "Downwind coning concept rotor for a 25 MW offshore wind turbine", Renewable Energy, Vol. 156, (2020), 314-327. (
  33. Yao, S., Chetan, M., Griffith, D.T., Mendoza, A.S., Selig, M.S. and Martin, D., "Aero-structural design and optimization of 50 MW wind turbine with over 250 m blades", Wind Engineering, (2021). (
  34. Bortolotti, P., Kapila, A. and Bottasso, C.L., "Comparison between upwind and downwind designs of a 10 MW wind turbine rotor", Wind Energy Science, Vol. 4, (2019), 115-125. (
  35. Ichter, B., Steele, A., Loth, E. and Moriarty, P., "Structural design and analysis of a segmented ultralight morphing rotor (SUMR) for extreme-scale wind turbines", Proceedings of 42nd AIAA Fluid Dynamics Conference, New Orleans, Louisiana, USA, (2012). (
  36. Crawford, C., "Parametric variations of a coning rotor wind turbine", Proceedings of 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, USA, (2008). (
  37. Ning, A. and Petch, D., "Integrated design of downwind land‐based wind turbines using analytic gradients", Wind Energy, Vol. 19, (2016), 2137‐2152. (
  38. Tossas, L.M. and Leonardi, S., "Wind turbine modeling for computational fluid dynamics", National Renewable Energy Laboratory, Technical report No. NREL/SR- 5000-55054, (2013). (
  39. Réthoré, P., "Thrust and wake of a wind turbine: Relationship and measurements", Master׳s Thesis, Technical University of Denmark, (2006). ( /media/Institutter/Mekanik/Sektioner/FVM/uddannelse/eksamensprojekt/mastertheses-fm/pierrerethore2006.ashx?hash=4E37E5F71D60845E67D3A018D7373297BA54C4E3&la=da).
  40. Burton, T., Sharpe, D., Jenkins, N. and Bossanyi, E., Wind energy handbook, John Wiley & Sons, (2001). (
  41. Chu, Y.J., Lam, H.F. and Peng, H.Y., "Numerical investigation of the power and self-start performance of a folding-blade horizontal axis wind turbine with a downwind configuration", International Journal of Green Energy, Vol. 19, No. 1, (2021), 28-51. (
  42. Betz, A., "The maximum of the theoretically possible exploitation of wind by means of a wind motor", Wind Engineering, Vol. 37, (2013), 441-446. (
  43. Menter, F.R., "Two-equation eddy-viscosity turbulence models for engineering applications", AIAA Journal, Vol. 32, (1994), 1598-1605. (
  44. Wilcox, D.C., Turbulence modeling for CFD, Second edition, DCW Industries, (1994). (
  45. Launder, B.E. and Spalding, D.B., Lectures in mathematical models of turbulence, Academic Press, (1972). (
  46. Griffith, D.T. and Ashwill, T.D., "The Sandia 100-meter all-glass baseline wind turbine blade:SNL100-00", Sandia National Laboratories, Albuquerque, report No. SAND2011-3779, (2011). (
  47. ANSYS. 12.0 user’s guide, Ansys Incorporayion, (2009). (, (Accessed: 16 July 2009).