Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer
Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer
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DOI：
10.1016/j.energy.2015.11.040
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发表时间：
2016-01
期刊：
影响因子：
9
通讯作者：
J. Na;E. Koo;D. Muñoz‐Esparza;E. Jin;R. Linn;Joon Sang Lee
中科院分区：
文献类型：
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作者：
J. Na;E. Koo;D. Muñoz‐Esparza;E. Jin;R. Linn;Joon Sang Lee
采用HIGRAD/FIRETEC-WindBlade模型对大型风电场（64台风力涡轮机）上方的气流进行高分辨率大涡模拟，该模型是一种高性能计算风力涡轮机-大气相互作用模型，采用拉格朗日致动器线方法表示旋转涡轮机叶片。这些高分辨率大涡模拟结果用于参数化推力和功率系数，其中包含有关风电场内涡轮机干扰效应的信息。然后将这些系数纳入WRF（天气研究和预报）模型，以评估大尺度模型中的干扰效应。在高分辨率WindBlade风电场模拟中，涡轮机之间的距离不足会造成涡轮机之间的干扰，包括动量和湍流强度的显著垂直变化。通过分析涡量和湍流强度的分布，进一步研究了尾流的特性。涡轮机和后涡轮机区域的象限分析表明，与其他象限相比，风力涡轮机引起的喷射运动占主导地位，这表明在出现强尾流恢复的位置，后掠角运动增加。区域尺度的WRF模拟表明，虽然由风电场引起的湍流混合部分扩散到上部区域，边界层深度没有显着的变化。速度差对涡轮机系数的局部分布并不十分敏感。然而，参数化湍流动能的差异约为5%，这取决于涡轮机系数分布。因此，考虑风电场干扰的涡轮机系数应用于大尺度模型的风电场参数化，以更好地描述亚网格尺度湍流过程。
High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines creates the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Therefore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.