考虑风切变影响的三维尾流模型风场实验

Experimental study on wind field of three-dimensional wake model considering the influence of wind shear

针对目前风力机尾流模型只能描述远尾流区域的尾流分布而忽略了近尾流区域的尾流特征的问题,基于双高斯函数,利用流量守恒定理并通过旋转修正推导了一个新的三维尾流模型。该尾流模型考虑了风切变的影响,并且能够描述近尾流区域以及远尾流区域的三维尾流分布特征。采用两台地基扫描激光雷达进行了风场实验,实验数据表明水平方向的近尾流分布类似于对称双高斯形、远尾流区域类似于对称高斯形,而垂直方向由于受到风切变的影响,在近尾流区域尾流分布类似非对称双高斯形、远尾流区域分布类似非对称高斯形。利用实测数据对三维尾流模型预测的水平剖面以及垂直剖面进行了对比验证,验证结果表明三维尾流模型的预测曲线和实验数据吻合良好,其平均相对误差大部分都在5%以内。新提出的三维尾流模型能够较好地预测风力机下游的整个尾流区域的空间分布,可为风电场的布局提供优化方案。

Aiming at the problem that the current wind turbine wake model can only describe the wake distribution in the far wake region and ignores the wake characteristics in the near wake region,this paper derives a new three-dimensional wake model based on the double-Gaussian function,using the flow conservation theorem and through rotation correction.The wake model considers the influence of wind shear and is able to describe the three-dimensional wake distribution characteristics in the near wake region and the far wake region.Wind field experiments were carried out with two ground-based scanning laser radars.The experimental data shows that the distribution of near wake in the horizontal direction has the symmetrical double-Gaussian shape,and the distribution of far wake area has the symmetrical Gaussian shape,while due to the influence of wind shear in the vertical direction,the distribution of wake in the near wake area has the asymmetrical double-Gaussian shape,and the distribution of far wake area has the asymmetrical Gaussian shape.The horizontal and vertical profiles predicted by the three-dimensional wake model are compared and verified by using the measured data.The validation results show that the prediction curves of the three-dimensional wake model are in good agreement with the experimental data,and the average relative errors are mostly within 5%.The newly proposed three-dimensional wake model can better predict the spatial distribution of the whole wake area downstream of the wind turbine and can provide an optimization scheme for the layout of the wind farm.