Altering Kinetic Energy Entrainment in Large Eddy Simulations of Large Wind Farms Using Unconventional Wind Turbine Actuator Forcing
Altering Kinetic Energy Entrainment in Large Eddy Simulations of Large Wind Farms Using Unconventional Wind Turbine Actuator Forcing
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使用非常规风力涡轮机执行器强制改变大型风电场大涡模拟中的动能夹带
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
C. Meneveau
中科院分区：
文献类型：
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作者：
C. Verhulst;C. Meneveau
在这项研究中，水平周期性的大涡模拟（LES）被用来研究湍流大气边界层流动的风力涡轮机在远下游部分的大型风力发电场的尾流已经合并和充分发展。为了通过增强风力涡轮机的平均动能（MKE）夹带来增加发电量，将假设的合成强迫应用于涡轮机转子位置的流动。合成强迫并不意味着代表任何现有的设备或控制方案，而是作为概念验证，为未来的设计提供信息。涡轮机采用传统的作动盘建模，非常规的合成力沿垂直方向施加，其大小和方向取决于转子盘处的瞬时速度波动;在一组旨在增强MKE的垂直夹带的LES中，规定了与正轴向速度波动结合的向下力，而负的轴向速度波动导致向上的力。强迫的大小与瞬时推力成正比，前因子的范围为0.1至1。合成垂直强迫被发现有一个显着的影响，由风电场产生的功率。与以前的研究结果一致，MKE通量的水平的涡轮机被发现变化沿着与总功率产生的风力涡轮机阵列。低速轴向流向下强迫的反向策略被发现对功率输出或卷吸几乎没有影响。测试的几个场景，例如，其中垂直力的大小与水平推力的大小相似，在实践中将很难实现，但是模拟用于识别通过涡轮机转子处的作用从流动修改中可能的功率增加的趋势和界限的目的。
In this study, horizontally periodic large eddy simulations (LES) are utilized to study turbulent atmospheric boundary-layer flow over wind turbines in the far-downstream portion of a large wind farm where the wakes have merged and the flow is fully developed. In an attempt to increase power generation by enhancing the mean kinetic energy (MKE) entrainment to the wind turbines, hypothetical synthetic forcing is applied to the flow at the turbine rotor locations. The synthetic forcing is not meant to represent any existing devices or control schemes, but rather acts as a proof of concept to inform future designs. The turbines are modeled using traditional actuator disks, and the unconventional synthetic forcing is applied in the vertical direction with the magnitude and direction dependent on the instantaneous velocity fluctuation at the rotor disk; in one set of LES meant to enhance the vertical entrainment of MKE, a downward force is prescribed in conjunction with a positive axial velocity fluctuation, whereas a negative axial velocity fluctuation results in an upward force. The magnitude of the forcing is proportional to the instantaneous thrust force with prefactors ranging from 0.1 to 1. The synthetic vertical forcing is found to have a significant effect on the power generated by the wind farm. Consistent with previous findings, the MKE flux to the level of the turbines is found to vary along with the total power produced by the wind turbine array. The reverse strategy of downward forcing of slow axial velocity flow is found to have almost no effect on the power output or entrainment. Several of the scenarios tested, e.g., where the vertical force is of similar magnitude to the horizontal thrust, would be very difficult to implement in practice, but the simulations serve the purpose of identifying trends and bounds on possible power increases from flow modifications through action at the turbine rotor.