Abstract—In this paper, power enhancement potential of NREL Phase VI rotor with bend-twist coupling is investigated with new numerical predictions. Geometry based bend-twist coupling is introduced to an NREL Phase VI turbine through a curved planform for power enhancement purposes. Fluid-structure interaction analysis is performed on two configurations of the blade, for a range of wind speeds to determine the induced elastic twist. The CFD predictions are verified with experimental data from NREL wind tunnel testing of an S809 airfoil. Two blade designs, one with an L spar and the other with a box spar, are modelled and the elastic twist is compared. The results show better elastic twist properties from an L spar, which is 0.67˚ from a swept blade with 1.5 m bend depth. A 1.89% power improvement is calculated due to elastic twist using BEMT.
 

Index Terms—fluid-structure interaction, bend-twist coupling, wind turbine blade