NUMERICAL ANALYSIS OF YAWED INFLOW EFFECTS ON A HAWT ROTOR

摘要

We describe a method of calculating yawed inflow effects on horizontal axis wind turbine rotors. Yawed inflow brings about asymmetric induced velocity distributions on the rotor plane due to inclined vortex wake constructions. Along with the effect from the undisturbed wind velocity components in the rotor plane, the asymmetric induced velocity gives rise to a periodically fluctuating load on the rotor blade. For the calculation of yawed inflow phenomena, an inviscid aerodynamic model based on the asymptotic acceleration potential method is adopted, where the rotor blades are represented by spanwise and chordwise pressure distributions composed of analytical first-order asymptotic solutions for the Laplace equation. Combined with dynamic stall models, the yawed inflow effects on the HAWT rotor have been calculated and compared with the experimental results. The calculation of the interaction between the structural dynamics and the aerodynamics has been also attempted for the flapwise oscillation of the rotor blade with flexibility at the root.