南京市不同功能分区风场特征的大涡模拟研究OACSTPCD

In this paper,Xinjiekou commercial area and Baixia Road residential area in Nanjing were selected as the research areas,and the effects of different incoming wind speeds and wind directions on the flow field were studied by using the PALM(Parallelized Large Eddy Simulation Model)model.Results show that the normalized wind profiles are similar under different inflow wind speeds,and the wind profiles are mainly influenced by the building morphology of the functional zones itself in general,and the variation of mean wind speed with height in the urban canopy is close to the exponential distribution in neutral stratification.However,the attenuation coefficient of the exponential wind profile calculated in the study ranges from 0.55 to 0.81,which is higher than the default value in the current urban canopy model,indicating that the current urban canopy model may have underestimated the wind speed attenuation in the densely built-up areas.The wind speed attenuation coefficient is mainly influenced by the frontal area,which increases with the increase of frontal area index,and the maximum decrease of wind speed at pedestrian height can reach 8％and 10％with the change of incoming wind direction in the studied commercial and residential areas,respectively.The wind speed at pedestrian height is generally larger in the streets and open spaces parallel to the incoming wind direction,and the wind speed can exceed the incoming wind speed in some areas due to the strong venturi effect,while the wind speed is lower in areas where buildings are densely distributed.The influence of the incoming wind direction varies in different urban structures,and the local wind field varies with the incoming wind direction at intersections,symmetrical and asymmetrical street canyons,and in multiple rows of buildings.