Impact of Modeling Approach on Flutter Predictions for Very LargeWind Turbine Blade Designs

摘要

Recent predictions for very large wind turbine blades have indicated that flutter may be a significant concern. Indeed,rnprevious predictions showed a decreasing flutter margin (ratio of flutter speed to operating speed) with an increasernin blade length. Previous flutter predictions were performed with a NASTRAN based flutter prediction tool that wasrnoriginally developed for vertical-axis wind turbine blades. Recently, a new flutter prediction tool has been developedrnusing a custom finite element framework. This new tool has the capability to provide a better geometric representationrnof a blade and also provides automated algorithms to perform iterative flutter calculations. In the course of applyingrnthe newly developed tool to very large blade designs, potential issues with modeling approaches were identified. Thernchoice of aeroelastic representation for flutter analysis of very large wind turbine blades was reevaluated, and revisedrnflutter analysis under different representations shows different flutter predictions for very large blade designs.