Design and testing of a deformable wind turbine blade control surface

Wind tunnel tests were conducted on a 1.3m chord NACA 63-418 blade section fitted with an adaptive trailing edge flap. The 20% chord flap had an aramid honeycomb core covered with a silicone skin and was actuated using servo motors. The honeycomb core had a high stiffness in the thickness direction but was compliant in chordwise bending. These anisotropic properties offer a potential solution for the conflicting design requirements found in morphing trailing edge structures. Static and dynamic tests were performed up to a Reynolds number of 5.4×10 ⁶. The tests showed that deflecting the flap from -10°to +10°changes the blade section lift coefficient by 1.0 in non-stalled conditions. Dynamic tests showed the flap to be capable of operating up to 9° s ^-1 using a 15V power supply. A two-dimensional static aeroelastic model of the morphing flap was developed to analyse strains, predict actuator requirements and study fluid-structure interaction effects. The model was used to conduct parametric studies to further improve the flap design. Potential applications include wind turbine blade load alleviation and increased wind energy capture. © 2012 IOP Publishing Ltd.