Morphing blade fluid-structure interaction

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 an aramid honeycomb core covered with a silicone skin and is actuated using servo motors. The honeycomb core has a high stiffness in the thickness direction but is compliant in flapwise 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 on the adaptive blade section up to a Reynolds number of 5.4×10⁶. 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. A two-dimensional static aeroelastic model of the morphing flap was developed to analyze 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.