基于三维代理模型的风力机尾流模拟

Investigation on three-dimensional surrogate model-based simulation of wind turbine wakes

  • 摘要: 为研究风力机尾流风场的特性,将风轮简化为多孔介质球体,提出了一种新的风力机三维代理模型。以河南省某地区陆上风电场为研究对象,通过无人机测风系统采集风电场的自由流与尾流数据,以实测来流风场为入流条件,采用修正的湍流模型参数建立数值模拟模型,并结合计算流体力学模拟数据,分析了风力机尾流在水平和垂直方向的分布特征。数值模拟结果表明,通过设置多孔介质模型的阻力系数可有效模拟风轮对流场的阻力效应;水平方向的尾流风速和湍流度呈对称分布,且近尾流区的湍流分布呈现双峰形式;垂直方向的尾流则表现为非对称分布。在轮毂高度处,尾流风速在下游2倍风轮直径(2D)处削减为来流风速的46%;随着尾流向下游发展,至6D距离处,逐渐恢复为来流风速的75%,同时湍流水平整体下降,叶尖高度的湍流增强效应也逐渐减弱。与实测数据的对比验证表明,模拟风速的均方根误差均在10%以内,湍流强度的误差大多在15%以内。说明所提出的代理模型能较为准确地计算尾流风速与湍流强度,为风力机尾流仿真的工程应用提供了新的思路。

     

    Abstract: To investigate the characteristics of wind turbine wake flow fields, a novel three-dimensional surrogate model for wind turbines is proposed by representing the rotor as a porous spherical medium. A combined approach of computational fluid dynamics and drone-based field measurements is employed to analyze the wake characteristics in both horizontal and vertical directions for an onshore wind farm in Henan Province, China. Free-stream and wake wind data were acquired using a drone-mounted anemometer system, and a numerical simulation model was developed with modified turbulence parameters. The field-measured inflow conditions were applied as the inlet boundary for simulations. Results indicate that adjusting the porous medium’s drag coefficient effectively captures the rotor's resistance effect. Horizontally, wake velocity and turbulence intensity exhibit symmetric distributions, with a bimodal turbulence profile observed in the near-wake region. Vertically, the wake shows asymmetry: the wind speed at hub height decreases to 46% of the inflow at 2D downstream (D being the rotor diameter) and recovers to 75% at 6D. Turbulence intensity decreases overall, and the tip-induced turbulence enhancement diminishes downstream. Validation against field data shows root mean square errors of simulated velocity within 10%, and turbulence intensity errors mostly within 15%. The proposed model provides an efficient and accurate method for 3D wake simulation, offering potential applications in wind farm layout optimization.

     

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