Literature Survey of Wind Turbine Aeroelastic Stability

A literature survey of wind turbine aeroelastic stability is presented. The subject received early interest as the emergent wind industry looked to lessons from the helicopter industry. There has not been a utility-scale turbine with flutter problems, but there is a concern over the behavior of larger, more flexible turbines. Blades of innovative design with bend-twist coupling and tip sweep are also a concern. Much of the aerodynamic modeling was formulated in the 1930s by Theodorsen. Modern authors have developed finite element structural models for eigenvalue solutions to the stability models. Calculations for a 1.5 MW turbine blade with bend-twist coupling show flutter speed at twice the rotor rotational speed. Comparisons were made to standard turbine aeroelastic codes showing good agreement, and the possibility of using these codes to check for flutter