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我国风能丰富的地区主要分布在沿海和“三北”地区,本文基于这些地区13个风电场全年共668572个测风样本得出了平原、山地和沿海三种地形不同地表状况下近地层风随高度变化特征。结果表明:虽然近地层风廓线形态多变,但风速随高度单调增加占绝大多数,可以用幂函数较好的拟合逐时风廓线;幂函数的指数即切变系数不仅受地表粗糙度影响,还受地形、风速大小以及热力层结影响,切变系数山区小,平原大,沿海比平原稍小;在我国北方地区,年平均切变系数有如下统计规律:山区草地为0.1以下,草原为0.15,同类地形随地表粗糙度增大而明显增大,大风段山区灌木比草地大30%。该结果可用于北方相似下垫面下的风能评估和风电场预可研调查。
Wind-rich areas in China are mainly distributed in the coastal areas and the “Three Norths”. Based on 668572 wind-measuring samples from 13 wind farms in these areas, the paper draws conclusions from the three landforms of plain, mountainous and coastal areas under different surface conditions Stratigraphic wind varies with altitude. The results show that although the wind profile of the surface layer changes in a variable way, the wind speed increases monotonically with the increase of height, and the power function can well fit the hourly wind profile. The exponent of the power function, that is, the shear coefficient, Roughness, but also by the terrain, wind speed and thermal stratification, the shear coefficient of small mountain, plain, coastal slightly smaller than the plain; in northern China, the annual average shear coefficient has the following statistical rules: mountain grassland 0.1 In the following, the grassland is 0.15, the similar terrain increases obviously with the increase of the surface roughness, and the shrubs in the mountainous area are 30% larger than the grassland. This result can be used for wind energy assessment under similar subsurface conditions in North China and pre-feasibility study of wind farms.