南京市不同功能分区风场特征的大涡模拟研究  

Large eddy simulation study of wind field characteristics in different functional zones of Nanjing City

作　　者：韩敬 潘哲 周慧敏 张宁[1] 周玉奇 陈燕 HAN Jing;PAN Zhe;ZHOU Huimin;ZHANG Ning;ZHOU Yuqi;CHEN Yan(School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China;Wujiang Meteorological Bureau,Jiangsu Suzhou 215200,China;PricewaterhouseCoopers Consulting(Shanghai)Co.,Ltd.,Shanghai 200126,China;Jiangsu Climate Center,Nanjing 210019,China)

机构地区：[1]南京大学大气科学学院,南京210023 [2]苏州市吴江区气象局,江苏苏州215200 [3]普华永道商务咨询(上海)有限公司,上海200126 [4]江苏省气候中心,南京210019

出　　处：《气象科学》2024年第3期572-582,共11页Journal of the Meteorological Sciences

基　　金：国家自然科学基金面上资助项目(U2342221,41975006,42075182);苏州市科技计划资助项目(SS2019033)。

摘　　要：本文选取南京市新街口商业区和白下路居民区作为典型研究区域,利用大涡模式(Parallelized Large Eddy Simulation Model,PALM)模拟不同入流风速和风向对流场的影响。结果表明,不同入流风速条件下归一化风廓线基本一致,风廓线总体上主要受到功能区自身建筑物形态的影响,在中性层结下城市冠层内平均风速随高度的变化接近于指数分布。而本文计算得到的指数风廓线衰减系数的范围为0.55~0.81,高于目前城市冠层模式中的默认值,说明目前的城市冠层模式对建筑物密集区域的风速衰减可能存在低估。风速衰减系数主要受迎风面面积的影响,随迎风面积指数的增加而增大。迎风面积指数随入流风向发生改变,在本文研究的商业区和居民区中,行人高度风速随入流风向的改变最大下降幅度可分别达8%和10%。行人高度风速一般在与入流风向平行的街道和开阔的空地上较大,在建筑物密集分布的区域风速较低,由于强烈的狭管效应部分区域的风速可以超过入流风速。不同城市结构中入流风向的影响也不同,在十字路口、对称和非对称街谷以及多排建筑物中局地风场随入流风向存在各种变化。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.

关 键 词：风环境 城市冠层 城市功能分区 大涡模拟 

分 类 号：P404[天文地球—大气科学及气象学]