CFD在建筑物对气象台站测风影响分析中的应用

Application of CFD to studying the effect of building on wind observations at meteorological station

受城市化、探测环境变化等人为因素影响,部分气象站风速序列存在不均一性,在使用这类气象站的风速资料时必须进行订正。本文以东山气象站为例,应用测站受建筑物影响前后各5 a的风速资料及探测环境历史沿革资料,利用计算流体力学方法(CFD)研究建筑物对气象站测风数据的影响。结果表明:建筑物与测风杆的相对位置不同,建筑物对测风的影响程度也不同,测站北面建筑物是影响该站偏北风风速观测的主要因素;研究不同风速下建筑的影响,可得模拟结果与输入风速间呈线性关系,由此建立风速订正关系式,订正后基本消除了建筑物对N方位风速的影响;订正受建筑物影响较小的NNE方位风速需考虑其他障碍物的影响。通过试验验证了CFD方法可用于定量评估建筑物对测风的影响,从而可重建受建筑物影响台站的风速序列。

Human factors such as urbanization and changes of observing environments cause inhomogeneity of wind speed series at some meteorological stations,so corrections need to be done when using this kind of wind speed data.Using the Dongshan meteorological station as a case study,the influence of buildings on wind speed data was analyzed by a CFD method in terms of five year wind speed data before and after the building erected,and the data of the historical evolution of observing environments.The results indicate that the influence of buildings on wind speed varies with the relative positions of wind measurement mast.The buildings in the north side of the station influence northerly wind speed significantly.According to the influence of buildings on the different wind speed,it can be learnt that the relationship between simulated and observed wind speeds is a linear correlation,so a correction formula of wind is established by this correlation relationship.The influence of buildings on north wind speed is generally eliminated after corrections.The other obstacles should be taken into account when revising wind speed of NNE direction because of light influence of buildings on NNE wind.It is proved that CFD could be applied for quantitative evaluations of influence of buildings on wind speed,thus wind speed series of station could be rebuilt.