DataSheet1_Correlations Between Wake Phenomena and Fatigue Loads Within Large Wind Farms: A Large-Eddy Simulation Study.pdf

This work proposes a methodology aiming at simulating the whole wind farm behavior, from the wake phenomena to the wind turbine fatigue loads, in a both accurate and efficient way and for a large range of operating conditions. This approach is based on Large Eddy Simulation (LES), coupled to an Actuator Disk (AD) approach. In order to recover pertinent fatigue loads with that wind turbine model, the blade trajectories are replicated through the disk and the AD aerodynamic forces are interpolated onto these “virtual blades” at each time step. The wake centerline is also tracked in the whole wind farm, in order to highlight the correlations between the wake phenomena and the wind turbine fatigue damage. The described methodology is deployed in simulations of the Horns Rev wind farm for several wind directions. The time-averaged power production is first compared to measurements and other LES results, with a very good agreement for large wind sectors. We then investigate the fatigue loads for several machines inside the wind farm and wind directions. We clearly show the link between the upstream wake movement and the resulting high and low frequency oscillations of the root bending moments and of the yaw and tilt moments, and therefore on the resulting fatigue equivalent loads. This study demonstrates the capacity of the numerical tool to accurately capture the wind farm flow and the rotor behaviors, as well as the correlations between the wake phenomena and the resulting fatigue loads.

本研究提出一种方法，旨在以精准高效的方式，在宽泛的运行工况范围内模拟风电场全流程运行行为，覆盖从尾流现象到风力发电机组疲劳载荷的全链条环节。该方法基于大涡模拟（Large Eddy Simulation, LES），并与致动盘（Actuator Disk, AD）方法耦合。为通过该风力发电机组模型获取有效可靠的疲劳载荷，需在每个时间步长内通过致动盘复现叶片轨迹，并将致动盘的气动力插值至这些"虚拟叶片"之上。本研究同时对整个风电场内的尾流中心线进行追踪，以揭示尾流现象与风力发电机组疲劳损伤之间的内在关联。所提出的方法已应用于Horns Rev风电场的多风向仿真实验中。首先将仿真得到的时均发电量与实测数据及其他大涡模拟结果进行对比，在大范围风扇区间内二者展现出极佳的吻合度。随后，本研究针对风电场内多台机组与不同风向工况开展疲劳载荷分析。研究清晰揭示了上游尾流运动与叶片根部弯矩、偏航力矩及俯仰力矩的高低频振荡之间的关联，进而对最终等效疲劳载荷产生影响。本研究证实，该数值工具可精准捕捉风电场流场与转子运行特性，同时准确反映尾流现象与疲劳载荷之间的关联关系。