The Science of Making Torque from Wind (TORQUE 2016)
European Academy of Wind Energy (EAWE)
October 5-7, 2016
Date of Presentation
Wind tunnel data are presented comparing upwind versus downwind operation of the National Renewable Energy Laboratory's Phase VI wind turbine. Power was not reduced as expected with downwind operation, which may be attributed to inboard three-dimensional effects. Average flap bending loads were reduced with downwind coning and compared well with prediction. Blade fatigue loads were increased with downwind operation; however, fatigue was mitigated with an aerodynamic tower shroud (fairing). The shroud needs to remain aligned with the freestream, demonstrated by an increase in fatigue loads from a 10° error in shroud alignment. Pressure data were acquired of the tower wake at the rotor location with and without the shroud installed. The bare-tower wake data compared well with previously published work. The shroud wake data at 10° error in alignment showed velocity reduction and turbulence approaching the bare tower values. Downwind operation, with an aligning tower shroud, should be considered for future designs given the load benefits of downwind coning.
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Larwood, S. M.,
Comparison of upwind and downwind operation of the NREL Phase VI Experiment.
Paper presented at The Science of Making Torque from Wind (TORQUE 2016) in Munich, Germany.