基于风场效应等代的真实山脉简化模型对比研究

Comparative Study on Simplified Models of Real Mountains Based on Similar Wind Field Effects

真实山脉地形崎岖复杂,山脊线两侧一般表现为不同的坡度,呈现明显的不对称性.为更好地反映真实山脉的地形与风场效应,在理想余弦山脉的基础上提出一种变截面余弦山脉简化模型.基于计算流体力学(Computational Fluid Dynamics,CFD)数值模拟,比较真实山脉、理想余弦山脉和变截面余弦山脉在平行山脉风向下地形特征点以及沿山脊线测点的水平平均风速加速比,并采用刚性直棒法对不同位置的导线风偏响应进行计算.结果显示:变截面余弦山脉和真实山脉的地形特征点水平平均风速加速比较为吻合;离地高度50 m处,变截面余弦山脉的沿山脊线水平风速加速比与真实山脉基本一致;由于参数限制,理想余弦山脉的山脊线走势较为独立,理想余弦山脉相比于真实山脉的水平风速加速比差别较大;采用变截面余弦山脉计算得到的风偏角能较好地反映真实山脉的风偏情况.尽管变截面余弦山脉的竖向风速与真实山脉存在较大差别,但变截面余弦山脉能较好地反映真实山脉的水平平均风速,具有风场效应的等代价值.

The real mountains are rugged and complex.The slopes on both sides of the ridge line are generally different,showing obvious asymmetry.To better reflect the terrain and wind field effects of real mountains,a simpli⁃fied model of the cosine-shaped mountain range with variable cross-section is proposed based on the cosine-shaped mountain range.Based on Computational Fluid Dynamics(CFD)numerical simulation,the horizontal mean wind speed-up ratio is compared between the real mountain range,the cosine-shaped mountain range,and the variable cross-section cosine-shaped mountain range in the wind direction parallel to the mountains.The rigid rod method is used to calculate the wind-induced swing response of transmission lines at different positions.The results show that the horizontal mean wind speed-up ratios in the terrain feature points are consistent between the variable cross-section cosine-shaped mountain range and the real mountain range.At 50 m above the ground,the horizontal mean wind speed-up ratio along the ridge line of the variable cross-section cosine-shaped mountain range is basically the same as that of the real mountain range.Due to the limitation of parameters,the trend of the ridge line of the cosineshaped mountain range is relatively independent,and its horizontal mean wind speed-up ratio is quite different from that of the real mountain range.The wind-induced swing calculated by variable cross-section cosine-shaped moun⁃tain range can much better reflect that of the real mountain range.Although the vertical wind speed of the variable cross-section cosine-shaped mountain range is quite different from that of the real mountain range,the former can better reflect the horizontal mean wind field of the latter.The proposed simplified model has similar wind field effects.