Profile stall characteristics, aerodynamic damping and design implications for wind turbine blades

摘要

Aeroelastic stability of wind turbine blades is considered and design implications are discussed. ^The investigation is motivated by recent concern on destructive 'edgewise' vibrations of modern, half-megawatt scale, blades. ^The work has two parts. ^First, results from an investigation on a one-section model problem are presented. ^The model is derived combining a spring-mass-damper equivalent of the structure with 'nonstationary' aerodynamics based on a linearized version of the ONERA dynamic stall model. ^The stability characteristics are then investigated in terms of the defining non-dimensional structural and aerodynamic parameters. ^In the second part, a full blade investigation is undertaken. ^The aerodynamic modeling includes wake induced effects whereas stall is not linearized. ^This direct approach permits to check the trends and indications from the first part on a commercial blade using a state of the art aeroelastic model. ^A parametric investigation is carried out with respect to the poststall behavior of the airfoils in the outboard region as well as with respect to the basic flap and edge eigenfrequencies. ^The paper presents the results of this study and discusses the corresponding design implications. ^(Author)