Comparison of calculation methods for wind shear exponent in complex terrain at altitude above 1000 meters

• Published in: Nong ye gong cheng xue bao Vol. 31; no. 6; pp. 218 - 222
• Main Authors: Deng, Shengxiang, Chen, Gang, Chen, Guibao
• Format: Journal Article
• Language: Chinese
• Published: 15.03.2015
• Subjects: Agricultural engineering; Constants; Exponents; Mathematical analysis; Meters; Roughness; Wind measurement; Wind shear; Wind speed
• ISSN: 1002-6819
• DOI: 10.3969/j.issn.1002-6819.2015.06.030

Wind measurements are generally performed below wind turbine hub heights due to avoiding higher measurement and tower costs. In order to obtain the wind speed at the hub height of the turbine, the measurements are extrapolated, assuming that the wind shear exponent is constant. Therefore, to obtain an accurate value of the wind shear exponent in a certain area at a certain time, only the local wind speed data can be used to calculate it. There are many different methods to calculate the wind shear exponent, and in this paper, four different methods are chosen, which are: the Panofsky and Dutton (PD) method, annual average wind speed method, wind profile method and all of the data method. The results show that due to the impact of ground roughness and the topography, wind shear exponents are different not only in different areas, but also when calculated by different methods even in the same area at the same time.