Computer simulated and measured trajectories of a scaled blade, as detached from a wind turbine, have been compared for a model-blade (0.6 m long), released from a custom-made blade-throwing machine. The simulations are based on a wing strip theory, using static airfoil data in combination with a dynamic stall model. The measured movement of the detached model-blade was found to be in good agreement with the simulations, although throwing distances in most cases tend to be longer in the simulations than in the experiments. The dynamic stall model mainly affects the ‘throwing width’ parallel to the wind direction and has only a negligible affect on the absolute throwing distance.
Get full access to this article
View all access options for this article.
References
1.
IversenJ.D. (1979), Autorotating flat-plate wings: The effect of the moment of inertia, geometry and Reynolds number. J. Fluid Mech., 92,2, pp 327–348.
2.
MadsenK.H.FrederiksenS.O.GjellerupC.SkjoldanP.F. (2004), Trajectories of Detached Blades (In Danish), Department of Fluid Mechanics, Technical University of Denmark.
3.
MontgomerieB. (1982) Horizontal axis wind turbine blade failure, blade fragment six degrees of freedom trajectory, site risk level prediction. Wind Energy Systems, Vol.2, pp. 389–401, BHRA, Cranfield.
4.
ØyeS. (1991) Dynamic Stall Simulated as Time Lag of Stall, Proc. of the Fourth IEA Symposium on the Aerodynamics of Wind Turbines, Paper 6, ed. McAnultyK.F., ETSU, Harwell Laboratory.
5.
ØyeS. (1980) Unsteady aerodynamic forces on 2-dimensional airfoil (in Danish). AFM Notat VK-58-800122, Lyngby.
6.
PedersenB.M.BuggeJ.A.C. (1980), On safety distances for wind turbines (in Danish). AFM Notat VK-63-800527, Lyngby. 1980.
7.
SheldahlR. E.KlimasP. C. (1981) Aerodynamic Characteristics of Seven Airfoil Sections Through 180 Degrees Angle of Attack for Use in Aerodynamic Analysis of Vertical Axis Wind Turbines, SAND80–2114, March, Sandia National Laboratories, Albuquerque, New Mexico.
8.
SørensenJ.N. (1984) On the Calculation of Trajectories for Blades Detached from Horizontal Axis Wind Turbines. Wind Engineering, Vol.8, No. 3.
