水平軸風車ロータ空力負荷に及ぼすタワーの影響に関する数値解析(流体工学,流体機械)  [in Japanese] Numerical Analysis of Tower Effects on Aerodynamic Force for Horizontal Axis Wind Turbine Rotor(Fluids Engineering)  [in Japanese]

The existence of tower in horizontal axis wind turbine system has sometimes a large effect on its surrounding fluid flow. In case of upwind turbines, the unsteady aerodynamic loads occur when the blades of a wind turbine are passing in front of the tower. The fluctuation of load causes a variation of power output and affects a fatigue life of the wind turbine, directly concerning the cost problems. The present paper describes a numerical method for calculation of the tower effects on aerodynamic loads, and shows the calculation results. For the calculation of aerodynamic loads on the rotor blades, an inviscid aerodynamic model based on the asymptotic acceleration potential method is adopted, which is capable of calculating the unsteady aerodynamic loads. In the model, the rotor blades are represented by spanwise and chordwise pressure distributions. The tower is represented by pressure distribution, in order to adapt the numerical model to that for calculation of aerodynamic loads on the blades. The calculation results show that the tower effects on aerodynamic loads depend on the distance between rotor plane and tower axis, and the tower radius, along with the operating wind condition.