Adaptive trailing edge for load alleviation on wind turbine blades

Wind tunnel tests have been conducted on a 1.3 m chord NACA 63-418 blade section fitted with an adaptive trailing edge flap. The 20% chord flap has a highly anisotropic aramid honeycomb core covered with a silicone skin and is actuated using servo motors. Honeycomb structures are known for their anisotropic properties. They display a high out-of-plane stiffness but are still compliant in-plane. These properties offer a potential solution for the conflicting design requirements found in morphing trailing edge structures. Static and dynamic tests were performed on the adaptive blade section up to a Reynolds number of 5.4×10^6. Tests have shown that deflecting the flap from −10° to +10° changes the blade section lift coefficient by 1.0 in non-stalled conditions. Dynamic tests have shown the flap to be capable of operating up to 9°/s using a 15 V power supply. Potential applications include wind turbine blade load alleviation and increased wind energy capture.