Study on Unsteady Aero-dynamic Load Analysis of Horizontal Axis Wind Turbine Rotor

复杂的地形成为WTGS（风力涡轮机发电机系统）拟建场地的吸引力。然而，复杂地形上的气流湍流强度远大于平坦地形上的气流湍流强度，这会增加风力涡轮机叶片上的气动载荷。因此，正确估计和/或测量复杂地形上的风的湍流特性对于WTGS和风力涡轮机叶片的设计非常重要。还需要通过数值计算来研究非定常流动条件对叶片载荷波动的影响。本文主要开展了以下三个方面的研究工作：采用基于面元法的数值计算方法，对水平轴风力机转子叶片在非定常流场条件下的局部攻角进行了分析。采用偏航来流条件进行计算，得到了攻角沿叶展方向的分布。发现在正弦M中波动 ...更多信息 当偏航失准角小到5 ° ~ 15 °时，在2003年11月19日至2004年3月23日期间，在日本爱知县的Shitara-Cho，利用多个测风塔进行了详细的风测量。通过分析风速的垂直分布和湍流的功率谱、相干性等特征，研究了地形坡度对风场的影响。水平轴风力涡轮机系统中塔架的存在对周围流体流动有较大的影响。在逆风风力涡轮机的情况下，当风力涡轮机的叶片在塔架的前面经过时，发生非稳定的空气动力学载荷。本研究还试图提出一种计算塔的存在对气动载荷的影响的数值方法。在旋翼桨叶气动载荷计算中，采用了基于渐近加速度势法的无粘气动力模型，该模型能够计算非定常气动载荷。在该模型中，转子叶片由展向和弦向压力分布表示。塔用压力分布表示，以使数值模型适应叶片上气动载荷的计算。少

Complex terrain has become attractive as the site proposed for WTGS(Wind Turbine Generator System). The turbulent intensity of the wind flow over the complex terrain is, however, much larger than that over flat terrain, and it brings about increased aerodynamic load on the wind turbine blades. Therefore it is important for the design of WTGS and wind turbine blades to estimate and/or to measure the turbulent characteristics of the wind over complex terrain correctly. It is also necessary to examine the effects of the unsteady flow conditions on the blade load fluctuation by means of a numerical calculation. In the present research, the following three projects have been performed.A local angle of attack to HAWT rotor blade has been analyzed in the unsteady flow conditions, by means of numerical calculation based on the panel method. Yawed inflow condition was adopted for the calculation, and the spanwise distribution of the angle of attack (A.O.A.) is found to fluctuate in sinusoidal m … More anner when the yaw misalignment angle is small as much as 5〜15 deg. When the misalignment angle is increased to 30 degree, the fluctuation of A.O.A.shows high frequency component because of the dynamic stall effects.The detailed wind measurements using multi wind-masts were also carried out at Shitara-Cho, Aichi in Japan during the period from November 19th in 2003 to March 23rd in 2004. The influence of the terrain slope on the wind has been examined by analyzing the vertical profile of mean velocity and the characteristics of the turbulence, such as the power spectrum and the coherence.The existence of tower in horizontal axis wind turbine system has a large effect on surrounding fluid flow. In case of upwind wind turbines, the unsteady aerodynamic loads occur when the blades of a wind turbine are passing in front of the tower. The present research has also tried to produce a numerical method for calculating the effect of tower existence on the aerodynamic loads. For the calculation of aerodynamic loads on the rotor blades, an inviscid aerodynamic model based on the asymptotic acceleration potential method was 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 the calculation of aerodynamic loads on the blades. Less