In this study, a Reynolds-averaged Navier-Stokes (RANS) numerical simulation with wind turbine simulated through actuator disk model was conducted to quantify the characteristics of wind turbine wake over two-dimensional Gaussian hills with different slope gradients. The simulated flow characteristics in the wind turbine wake, such as velocity deficit, wake expansion and wake centerline, were compared with those given by the Jensen wake model to quantitatively evaluate the accuracy of the current engineering wake model for the optimal design of wind turbine layout over complex terrain. For the gentle slope hill, the topography behind the wind turbine has a significant effect on the wake characteristics, which is not taken into account in the Jensen wake model. A new method for calculating wake velocity is proposed based on the local speed-up factor and the simulated velocity in the wake of wind turbine sited on flat terrain that can more reasonably predict the wake velocity over complex terrain. For the steep slope hill, the propagation of wind turbine wake is not related to the hill shape in the region behind the hilltop. The assumption that the wake centerline follows the surface of the hill in the Jensen wake model is no longer applicable. The recovery of wind turbine wake in the far wake region was always faster for the steep slope hill compared with the gentle slope hill case. This acceleration of wake recovery is thought to be closely related to the separation flow at the lee side of the hill, which highly restricts the downward deflection and expansion of the wind turbine wake.

在本研究中，通过致动器盘模型对风力涡轮机进行雷诺平均纳维-斯托克斯 (RANS) 数值模拟，以量化具有不同坡度的二维高斯山丘上的风力涡轮机尾流特征。将风力机尾流中的模拟流动特性，如速度赤字、尾流扩展和尾流中心线，与 Jensen 尾流模型给出的特性进行比较，以定量评估当前工程尾流模型对风力机布局优化设计的准确性在复杂的地形上。对于缓坡山地，风电机组后面的地形对尾流特性有显着影响，Jensen尾流模型没有考虑这一点。提出了一种基于局部加速因子和模拟的平地风力机尾流速度计算尾流速度的新方法，可以更合理地预测复杂地形上的尾流速度。对于陡坡山丘，风力机尾流的传播与山顶后方区域的山丘形状无关。Jensen 尾流模型中尾流中心线沿着山丘表面的假设不再适用。与缓坡山情况相比，陡坡山的远尾流区风力机尾流恢复总是更快。这种尾流恢复的加速被认为与山背风侧的分离流密切相关，这高度限制了风力机尾流的向下偏转和扩展。