复杂地形与风力机涡流形成机制及其耦合演化研究

Coupling of wind turbine wakes, turbulences flowing over hills and the multi-scale vortex flows in atmospheric boundary layer constitute a complex vortex system and influence wind resource assessment and wind power forecasting in complex terrain significantly. The present numerical studies based on the finite volume method have difficulties in dealing with complex terrain and the rotating wind turbine rotor while the experimental studies mainly carried out in wind tunnels fail to meet the conditions in flow similarities. To overcome these difficulties and to better understand the multi-scale vortex system in wind farm, this project plans to propose a new numerical method based on the adaptive LBM through theory analysis to carry out numerical simulations of the vortex system in wind farm and apply lidars and masts to measure wind field in real wind farms. The aims of this project are: to study how turbulent flow over hills and wind turbine wakes generate vortex and how these multi-scale vortices develop and interact with each other; to propose the conditions of the vortex instability, to understand the influence of complex terrain, the tip speed ratio of a wind turbine and atmospheric stability on the evolution of these vortices; and finally to reveal the mechanisms of the production, merging, tearing and stretching of the vortices. Research results of this project can benefit the wind farm micro-sitting and optimization of wind turbine operation in complex terrain.

风力机尾流、山地绕流以及大气边界层中的多尺度涡流耦合构成的复杂涡流系统，是影响复杂地形风电场风资源评估可靠性和风功率预测精度的主要因素。现有研究手段中，基于有限体积法的数值研究存在曲面处理和运动边界处理困难，风洞试验难以满足众多相似准则要求，造成复杂地形风电场涡流系统的演化规律仍不明确。针对现有研究手段和对风电场涡流系统认识的不足，本项目拟通过理论分析建立适合于处理复杂边界和流动结构的自适应网格玻尔兹曼方法，开展风电场涡流数值研究，结合激光雷达和测风塔开展风电场涡流现场测量试验，探索典型地形诱导和风力机旋转剪切的涡流初生机理，研究典型复杂地形绕流和风力机尾流涡流及其耦合的时空多尺度演化特征，提出涡流失稳的临界条件，掌握复杂地形、风力机叶尖速比以及大气边界层热稳定性等对涡流演化的影响规律，揭示复杂地形风电场涡流的初生、合并、撕裂和拉伸的动力学机制。项目研究可以为风电场规划设计与运行提供参。

复杂地形风电场中，风力机运行在复杂的大气边界层湍流、地形绕流和风力机组尾流耦合作用下的空气流场中，过去由于对流场结构认识、理解的不足，给实际风电场工程的规划、设计和运行带来了很多的难度。本项目开展：建立基于自适应LBM方法的复杂地形风电场涡流高精度仿真模型、构建复杂地形风电场涡流可视化及其特征识别与提取方法、研究典型复杂地形与风力机诱导流场耦合演变规律、研究基于LBM-LES方法的风力机尾流及地形耦合流动、研究基于修正致动线模型和大涡模拟的风力机尾流及其叠加特性、研究基于LBM-LES方法的风力机非定常尾流特性、研究大气稳定度对复杂地形风力机功率和尾流影响、研究近—远尾流一体化模型、开发工程尾流模型、开发风电场微观选址软件。得到的研究结果包括：典型地形诱导和风力机旋转剪切的涡流初生机理、典型复杂地形绕流和风力机尾流涡流及其耦合的时空多尺度演化特征、涡流失稳的临界条件，复杂地形、风力机叶尖速比以及大气边界层热稳定性等对涡流演化的影响规律，复杂地形风电场涡流的初生、合并、撕裂和拉伸的动力学机制。项目研究可以为风电场规划设计与运行提供参。