抄録
BEM (Blade Element and Momentum) theory is useful for load calculation of wind turbines, as hundreds of load cases must be calculated for aero-elastic models with controllers considered. Modeling of tower shadow effects is essential for design of downwind turbines, which are promising in complex terrains. Present study proposes a new modeling method for tower shadow effects on the basis of load equivalence. It considers aerodynamic interaction between rotor and tower and transient passing through tower wake. Those phenomena were ignored in former modeling, which are defined on the basis of wind speed profile behind isolated tower. Load equivalent model of SUBARU 80/2.02 MW downwind turbine was defined based on load transients calculated by wind turbine CFD in operating condition. The model was verified through field tests. Furthermore, a case study made clear that former models provide 10-30% larger fatigue loads than the present proposed load equivalent model. Present method makes downwind turbines competitive to upwind turbines.
