Statistics Of Strong Wind In Urban Boundary Layer Of Beijing

With the success of the 2008 Beijing Olympic Games, urban construction in Beijing is accelerated, large-span and high-rise buildings are put in the leading place, but the wind load is one of the main controlling loads of the design of these structures. Therefore, the study on the wind characteristics near ground in urban boundary layer has become an urgent need as an important issue.This paper depends on Institute of Atmospheric Physics 325m meteorological tower and statistically analyzes the near ground strong wind turbulent characteristics in Beijing by the three-dimensional measured turbulent wind data of 2005-2007 years. Primarily, the mean wind speed, directions, turbulence instensity, turbulence integral scale,wind speed spectrum and some other characters are statistically analyzed.The results have revealed that:(1) It is dominated by the northwest wind and north wind in the winter but the northwest wind and west wind in the summer above 47m height.(2) In the range of 7.0-12.0m/s wind speed, with the increasing of the mean wind speed segment, the statistical wind profile is between the class C venue type and class D venue type of the norms in China. (3)Turbulence intensity decreases with the rising of the mean wind speed, however, there is not a very significant interact between the relationship of the mean wind speed and turbulence integral scale. (4) The linear correlation is very obvious among the measured turbulence intensities and with the growing of the mean wind speed segment, the ratio of the linear correlation becomes smaller and smaller. (5) With regard to samples of strong wind, the statistical alongwind turbulence intensities are closer to the class 5 venue type of Japanese norms, the statistical alongwind turbulence integral scale is almost close to Japanese norms in 47m and 120m and is greater than Japanese norms in 280m. (6) The measured power spectra can fit Von Karman spectrum very well in alongwind direction, can fit Simiu-Scanlan spectrum very well in lateral wind direction, and can fit Lumley-Panofsky spectrum very well in upward direction. Finally, the corresponding forms of alongwind, lateral wind and upward spectrum are deduced with the uniform format of fluctuate based on Kolmogrove theory, and then the corresponding paramaters are also presented.