Assessment of aerodynamics models for wind turbines aeroelasticity

A comprehensive computational tool for the aeroelastic analysis of horizontal axis wind turbines (HAWT) is presented. The proposed aeroelastic tool couples a nonlinear beam model for blades structural dynamics with an unsteady state-space sectional aerodynamic model taking into account dynamic stall. Three-dimensional wake inflow effects are described by a Boundary Element Method for the solution of incompressible, potential, attached flows. To this aim, different coupling approaches are compared. The resulting aeroelastic differential system is integrated through the Galerkin method, with the introduction of a novel technique for the spatial integration of the additional aerodynamic states related to wake vorticity and dynamic stall. Periodic blade responses are determined by a harmonic balance approach. The effectiveness of the proposed unsteady aerodynamic modelling is discussed, with numerical and experimental comparisons.