In this paper the aeroelastic stability of a wind turbine rotor in the dynamic stall regime is investigated. Two dimensional stall flutter models have been chosen for the aeroelastic stability analysis. Two different aeroelastic models have been considered. First, a pitching oscillation, and second, a flap-edgewise oscillation of an airfoil. Previous nonlinear aeroelastic analysis on such systems are not exhaustive. Parameters like structural non-linearity and initial conditions have not been studied, while these have a significant influence on the overall dynamics. They have now been taken up in the present analysis. The overall study helps towards a better understanding of the stall flutter mechanism in such aeroelastic systems. The study has found a strong influence of structural nonlinearity on the bifurcation pattern. Initial condition, too, plays an important role on the stability behavior as well as on the bifurcation pattern. Other system parameters of influence are nondimensional airspeed and external forcing. Interesting dynamical behavior like period-three and also super-harmonic and quasi-harmonic response have been found in the forced system, not reported before.
Aeroelastic Analysis of Preset Angle for A Typical Airfoil Section with Cubic Nonlinear Stiffness