Numerical Analysis of Aero-elaiticity Effect on Horizontal Axist Wind Turbine Rotor designed as a Soft Structure

该项目旨在开发数值方法来模拟风力机转子所经历的湍流风场并预测其对气动载荷的影响。湍流风场模拟产生旋翼平面内多个点的湍流风速时间序列，用于气动载荷分析，同时考虑了某一点的风时间序列与其他点的风时间序列的相关性。风场模拟模型是基于傅里叶合成方法(Veer模型)构建的。在该模型中，所需的输入是湍流的功率谱密度(PSD)和相干函数，它们定义了旋翼平面上任意两点之间的互谱密度(CSD)。通过在PSD和CSD集合中添加随机位相，可以确定模拟风复傅立叶系数的矢量。通过对矢量进行逆傅立叶变换，得到了风速的时间序列。在计算旋翼叶片上的气动载荷时，采用了基于渐近加速度势方法的无粘气动力模型。该计算模型可以方便地计算尾迹引起的旋翼平面内流动不稳定的影响。用ONERA方法考虑了由动态失速效应引起的非定常气动载荷，通过模拟风场与现场试验结果的对比，验证了湍流风场模拟器的有效性，并分析了旋翼上的气动载荷(例如，风速、风速等)对风场的影响。风的湍动特性给风力机带来了复杂的气动载荷，这是风力机叶片结构设计过程中必须考虑的问题。本计算模型有可能开发出简单的设计工具。

This project is aimed at the development of numerical methods to simulate a turbulent wind field and to predict its influence on aerodynamic loads experienced by a HAWT rotor.The turbulent wind field simulation generates time series of turbulent wind speed at several points in a rotor plane for use in the aerodynamic loads analysis, taking account of the correlation of the wind time series at a certain point with that at every other point. The wind field simulation model is constructed on the basis of a Fourier synthesis method (the Veer's model). In this model, the required inputs are the power spectrum densities (PSDs) and the coherence functions of the turbulent wind, which define the cross spectral densities (CSDs) between any two points in the rotor plane. The vector of complex Fourier coefficients of the simulated wind can be determined by adding random phases to the set of PSDs and CSDs. By performing an inverse Fourier transform of the vector, the time series of the wind is obtained.For the calculation of aerodynamic loads on the rotor blades, an inviscid aerodynamic model based on an asymptotic acceleration potential method is adopted. This calculation model can easily evaluate the effects of the flow unsteadiness in the rotor plane induced by the wake. Unsteady aerodynamic loads caused by the dynamic stall effects are taken into account by using the ONERA method.The validity of the turbulence wind field simulator is checked by means of comparisons of the simulated wind with experimental results of field tests, and it is analyzed how the aerodynamic loads on the rotor (ex. flapping moment) respond to turbulence characteristics of the wind incoming to the rotor.Turbulence characteristics of the wind incoming to a turbine rotor bring about complicated aerodynamic loads on the wind turbine, which must be considered in the structural design process of the rotor blades. The present calculation model has a possibility to develop a simple design tool.