高层建筑底部区域行人风环境试验研究

Experimental Investigation on Pedestrian-level Wind Environment Around a High-rise Building

对单个方形截面高层建筑底部区域12m范围内的行人高度风环境进行试验研究。研究了不同风向角下加速比、平均风速比等参数的分布与变化规律,并以广州为例,利用Lawson风环境评价准则对该区域处于强风下的风环境进行了评价。结果表明各风向角下的最大加速比大致相等,约为1.9,且均出现在建筑背风面角隅位置。平均风速比大于0.75的区域也出现在建筑背风面角隅,此处易引起行人风环境不适。建筑周围12m范围内风环境不适的区域面积在与墙面正交风向时达到最大,应重点关注下洗(Downwash)效应造成行人高度处风速增大的影响;在斜风向20°~70°范围内通风不利的区域面积较大,对空气污染物扩散不利。建筑迎风面和背风面角隅位置出现最大等效阵风风速,应当对建筑角隅区域行人活动加以限制或提醒。

The pedestrian level wind environment around a single square cross-sectional high-rise building(within 12 meters of bottom area)was investigated in the wind tunnel,and the distribution and variation of the parameters such as speed-up ratio and RM(mean wind velocity ratio)at different wind direction angles were studied.Meanwhile,by employing the meteorological data of Guangzhou and the Lawson criterion of wind comfort,the pedestrian level wind environment under strong wind in this region was evaluated.The results show that the maximum speed-up ratios at different wind direction angles are approximately equal to 1.9,and all appear at the corner of the leeward side of the building.The areas with the RM greater than 0.75 also appear at the corner of the leeward side of building,which is likely to cause pedestrian wind discomfort.Besides,the area of pedestrian wind discomfort is the largest when the wind direction is perpendicular to the wall.Attention should be paid to the increase of wind speed caused by the downwash effect at pedestrian level.In the wind direction angle range of 20 to 70 degrees,the area with unfavorable ventilation is quite large,which may cause adverse results in diffusion of air pollutants.The greatest gust equivalent mean wind speed appears at the corners of the windward and leeward sides of the building,and pedestrian activities in these areas should be restricted or reminded.