Research on Flutter Characterization of Flexible Blade Response under Typhoon Operating Conditions

Abstract

Wind turbine blades, being flexible, are susceptible to damage during typhoons. Studying the aeroelastic response of these blades in typhoon conditions is crucial for providing a theoretical foundation for their optimization and design. This research focuses on the NREL 5 MW flexible blade, employing the B-L stall model for dynamic inflow and geometrically exact beam theory to develop an aeroelastic model capable of predicting the blade’s flutter limit. Through quantitative analysis, we assess the stability of the wind turbine’s flexible blade under typhoon conditions and examine the blade tip’s transient response. The findings indicate that the model’s flutter speed is 21.5 rpm, marked by a significant increase in tip deflection’s mean square error of over 80% and a coupling of flapwise and torsional modes at 4.81 Hz. The blade tip’s transient response under typhoon conditions does not satisfy the flutter criterion, thus preventing instability. Under typhoon conditions, the deflection in the flapwise, edgewise, and twist directions of the blade shows an increase of 12.1%, 10.5%, and 119.2%, respectively, compared to standard operating conditions.

Keywords

• typhoon
• wind turbine
• aeroelastic instability
• dynamic response
• OpenFAST