Aero-Elastic Stability Analysis Tools for Large Wind Turbine Rotor Blades

摘要

Although modern large size wind turbines do not operate in stall, the trends associated with scaling of dimensions reduce the stability of edgewise blade vibrations. At ECN Wind Energy the aero-elastic vibrations of rotor blades are investigated by participation in the research projects STABTOOL, DAMPBLADE, and the ongoing STABCON project. The developments within these projects have resulted in some aero-elastic stability analysis codes. The relatively simple but fast code BLADMODE can be used to investigate modifications of the blade structure on the aero-elastic behaviour. These investigations include Structural Pitch, which is a modification of the direction of vibration realised by shifting the UD layers. It was also shown that operation at high lift coefficients gives a reduced damping of the edgewise vibrations because at high lift values, airfoils show an increasing drag coefficient with angle of attack (drag stall).