Study on Aerodynamic Performance Characteristics of Horizontal Axis Wind Turbine under Combined Inflow Condition

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This study aims at examining the effects of combined inflow condition that includes extreme wind condition such as extreme wind speed and wind gust, and ordinary wind condition (turbulent characteristics, wind shear, etc.) on the aerodynamic performance characteristics of the horizontal axis wind turbine (HAWT) rotors, by using numerical methods, which leads to establish a procedure to estimate the generating power of WTGS (Wind Turbine Generator System) and its life time from the aerodynamic point of view.Concerning about the modeling of the inflow condition and their effects on the HAWTs, following works has been done during the period.- By using statistical method, temporal and spatial gust shapes were extracted from the time series of measured wind speed at multiple points on the meteorological masts and are compared with some theoretical models.- The aerodynamic effects of the wind gust on the HAWT rotors are examined numerically by using the preceding theoretical models and the load calculation model based on acceleration potential method.Some numerical studies on fluid-construction coupled vibration of the HAWT rotor blades have been done as follows.- In the calculation, the turbine blade is represented by a multi-body dynamic model, and the effects of the inflow yaw misalignment on the coupled vibration have been examined for the wind tunnel experimental model at NREL. From comparison with the experiments, the first and second resonant frequencies for the flapwise oscillation of the blades can be estimated correctly by the present calculation model.- For the flapwise oscillation of the rotor blades, an aerodynamic damping force effects have been found to exist due to the fluctuation of the relative wind speed to the blade by the blade oscillation.Moreover, studies on aerodynamic noise characteristics and power generation for field wind turbines have been performed experimentally.