某高层建筑周围行人高度风环境试验研究

通过缩尺比为1∶300模型的风洞试验,研究了在16个来流风向下某高层建筑建成前后周围的风环境。结合当地的气象风速资料,分析了建筑物周围26个位置的行人高度风环境在坐、站、行三种情况下的舒适性状况,并根据试验结果提出了改善局部风环境的建议和措施。     

某TOD商业综合体室外风环境绿化改进研究

以公共交通为向导开发(TOD)的商业综合体因其复杂特征容易造成室外风环境的局部恶化,但是,绿化能够改善室外风环境.采用CFD模拟方法和LES湍流模型,结合上海市风环境特征,以上海市某TOD商业综合体为例,研究满足绿色建筑评价标准中满足人行高度处风速＜5 m/s和儿童活动区域风速＜2 m/s的目标,依据种植树木前后的数值模拟对比,对综合体周围无绿化和现有绿化方案进行分析,并根据树木特性及对TOD商业综合体周围风环境的影响提出更为合理的绿化布局,以此满足室外行人和儿童活动区域的舒适度要求.研究结果表明:在风速过大的区域,树木阻风作用好,在冬季,项目地块内风环境最大风速下降约1 m/s,可为利用绿化树木阻风的室外风环境绿化改进提供参考.     

高层建筑对周围低层建筑的风环境影响研究

高层建筑的出现会改变其周围风环境,为研究高层建筑对周围低层建筑风场的影响,建立CAARC标准模型进行模拟并与风洞实验结果对比,验证选用的湍流模型、边界条件和建模方法的有效性;为重点研究高层建筑布局和高度的影响,将统计样本按照建筑布局分为4类并结合规范选取3种建筑高度进行数值模拟,分别得到居住区内风速、风速比分布图以及典型测点的最大风速曲线。通过对比居住区内最大风速、最大风速比和典型区域风速变化曲线发现:高层建筑邻近街道区域风速明显增大,迎风面拐角处风速增大现象尤其明显;高层建筑布局对风场分布形态有重要影响,对居住区最大风速影响不大,而高层建筑高度的影响与之相反。给出了当前边界条件不同高度比下的最佳高层分布情况。     

横风向响应的气动弹性模型风洞试验研究

应用国际通用的CAARC模型进行了多自由度气动弹性模型在模拟风场中响应的试验,分析了结构在不同风速与不同风向角下的横风向响应变化规律,其结果可供高层建筑结构风振响应理论研究参考.     

厦门五缘湾两侧风场同步实测试验分析

为探究厦门五缘湾周边区域风场参数分布规律,利用激光雷达开展了该区域两点位12个高度层的实时同步风场测量试验,对比分析了两点位风速、风向、地面粗糙度等参数变化规律,完成了实测粗糙度系数与公路桥梁抗风设计规范值对比工作。分析结果表明:厦门五缘湾两侧区域测点风速变化规律一致,风速值白天大于夜晚,最大风速可达9.23m·s-1;风向受地形变化影响较大,两测点风向因地形差异而关联性较弱;风速稳定的条件下,地面粗糙度α值随风速增加而增加;测点α值均小于规范值,高层建筑风荷载设计取值更加保守。     

室外风环境实测及PHOENICS模拟对比分析研究——以徐州高层小区为例

基于对阿尔卡迪亚小区和紫金东郡小区室外风环境的实测和结果分析,研究了徐州高层建筑室外风环境问题,并在分析高层住区建筑规划设计对室外风环境的影响之后,总结相关优化设计策略。通过中国气象数据网获取实测时间段内室外风速平均值和主导风向,利用软件模拟室外风环境并评价结果。通过对比软件模拟结果与实测结果,得出实测结果与软件模拟结果具有关联性;在相同的室外风环境条件下,所得各测点风速大小规律基本吻合。     

西安市城区通风环境数值建模及分析

近年来,城市建筑的高度和密度不断增加,对城市通风环境产生了很大影响。针对西安市绕城高速以内区域,建立了城区建筑、道路等几何模型,在此基础上建立了城市风环境数值仿真模型。通过数值仿真,分析了在冬季主导风ENE风向下,区域风环境的现状,包括风速分布、通风能力等。研究表明,建筑布局、街道布局、建筑密度和风向会对区域风速分布及通风能力有明显影响。控制城市内十字路口处建筑高度及建立城市主导风向上通风廊道有利于城市内的通风。     

杏林湾CBD人行区域风环境模拟评价与实测对比

为了评估厦门地区高层建筑对周围人行高度风环境安全性和舒适性的影响,选取杏林湾CBD为研究对象,通过PHOENICS软件对不同工况的风环境进行模拟与评价。分析模拟结果,结论表明:(1)该片区夏季人行区域风环境良好,冬季和过渡季节部分区域风速偏大导致舒适度下降。(2)该片区大风天气行人区域发生危险的概率较高,需引起重视。(3)将模拟结果同实测数据进行对比,风速分布较一致,大小存在一定的误差。其次,针对风环境舒适性和安全性,提出了相应的措施和建议。     

室外风对火焰特征影响的数值模拟研究

为研究高层建筑或超高层建筑中室外风在玻璃破碎后对火焰特征的影响,运用FDS数值模拟方法,对风速为0～24m/s的17个自由燃烧算例进行了模拟研究,拟合了适用于较大室外风速条件下的火焰长度及其倾角计算公式,并与Dfaveri模型、Drysdale模型进行了对比分析。结果表明:室外风速增大会使火焰长度及其向上风向倾斜的角度减小,但会使火焰向下风向倾斜的角度增大。     

高层建筑立面设计的微造型思考

本文针对不同开孔立面造型条件下高层建筑的空气风速度场进行了分析研究,以此为根据为高层建筑的立面造型设计提供依据。结果表明在高层建筑楼体开口面积相同的情况下,立面开孔数量越多,建筑物后面的垂直风速越强且分布越均匀,行人高度处的风影面积越小。对于孔洞分布,最佳孔洞间距与孔洞尺寸之比在1～3之间,可以更有效地分散建筑周围的热量,并在最低层减弱风速。除此之外,在高层建筑中,开孔的数量和分布也会对建筑物周围的风环境产生不同的影响。本文的结果有助于建筑师在未来的高层建筑立面设计中更加科学的进行立面洞口造型的设计,保证周围风环境安全的同时,创造有利的风环境,加快污染物散发,营造健康、舒适的城市环境。     

住宅小区风环境数值模拟

建立了某典型住宅小区风环境的物理和数学模型,并应用计算流体动力学方法求解了三种来流角度下的稳态三维湍流流场,给出了速度、压力、湍流度参数的分布;分析了街区涡流、巷道风及活塞风等效应,研究了风压作用下建筑群的迎风及背压区,讨论了湍流入流边界对合理湍流分布的作用;比较了不同来流角度下五个观测点位置的风环境参数。     

拟建高层建筑风环境对周边建筑遗产影响评估——以广州同盛机器厂旧址为例

高层建设项目将对风环境造成严重影响,给遗产保护利用带来新的问题与隐患。于是在城市规划设计早期,评 估拟建高层建筑风环境对周边建筑遗产的影响显得尤为重要。以规划中的广州白鹅潭国际中心商贸区及其中文物建筑 群——同盛机器厂旧址为例,应用 CFD 软件 Phoenics 模拟典型工况下拟建高层建筑风环境的影响。结果显示：①强台 风工况下,屋面风荷载未超过安全限值,由风压分布得出易受破坏部位;②“回南天”工况下,区域通风效果较好,但 风影区影响较大,存在加重生物侵害的隐患;③夏冬季工况下,风廊改善夏季风环境的作用明显,冬季在高层建筑附近 出现下行的高速冷风。依据建筑遗产受影响情况作出预评估,可指导城市高层建筑建设与周边建筑遗产保护协同进行。     

Pedestrian-level wind environment near a super-tall building with unconventional configurations in a regular urban area

Unconventional configurations of tall buildings are noticeably different from their counterpart of traditional building designs but nevertheless, the unconventional configurations have often been adopted for tall buildings without their impact on the pedestrian-level wind environment (PLWE) fully understood. To fill the existing knowledge gap, this study investigates the PLWE near a 400 m super-tall building with various conventional and unconventional configurations in a regular urban area. Computational fluid dynamics (CFD) simulations were conducted for three incident wind directions (θ = 0°, 22.5°, and 45°) to investigate mean wind speed at the pedestrian level using the three-dimensional (3D), steady-state, Reynolds-averaged Navier-Stokes (RANS) technique. The results reveal 1.5- to 2.5-fold increase in maximum wind speed in the urban area after the construction of a super-tall building. The magnitude of the maximum wind speed and areas with high and low wind speeds in the PLWE, however, significantly vary with building design and incident wind direction. The configurations with sharp corners, large plan aspect ratios and frontal areas and the orientation consistently show a strong dependency on incident wind direction except the one with rounded plan shapes. The location of building openings and direction of building inclination are two other factors that modify the PLWE in an urban area. Moreover, the projected width of the super-tall building at a height slightly above the roof level of surrounding buildings is critical for estimating the areas of high and low wind speed at the pedestrian level.

     

基于软件模拟室外环境规划设计实例分析

本文利用Fluent软件模拟规划小区的热环境。通过Fluent对风绕小区建筑时的流场进行了模拟分析,在得出模拟结果和对所选春季流场数据进行分析的基础上,提出小区在规划前期需考虑建筑物密集程度、风向及朝向位置的重要性,以及其方案的可行性。对某实际复杂建筑小区的风速场进行了模拟,实现了理论与实践的结合。引出了建筑规划设计的重要性,同时说明了计算机模拟软件结合小区规划的优越性。通过对建筑楼的室外环境的模拟分析实例,给出了小区在规划前期的室外环境布局的相关建议。     

Prediction of wind environment in different grouping patterns of housing blocks

The idea of utilising natural ventilation for passive cooling has increasingly attracted the attention of researchers. In urban areas, this is intended to improve the outdoor and indoor thermal conditions without compromising the principles of sustainable building design. This study investigates the effect of building grouping pattern on the resulting wind environment in the outdoor spaces and the resulting ventilation potential of these buildings. A parametric three-dimensional modelling study has been carried out using computational fluid dynamics (CFD). Several configurations of housing blocks exposed to different wind directions have been modelled and compared considering the hot climate of Gaza. It has been found that grouping pattern of buildings as well as their orientation with respect to wind has a dramatic effect on the resulting airflow behaviour and pressure fields. Configurations that contain a central space articulated by buildings and oriented towards the prevailing wind can offer better exposure to air currents and better containment of wind. Such configurations are recommended for better wind-driven ventilation, where the main design objective is passive cooling.     

Creating sustainable cities one building at a time: Towards an integrated urban design framework

One of the tenets of urban sustainability is that more compact urban forms that are more densely occupied are more efficient in their overall use of space and of energy. In many designs this has been translates into high-rise buildings with a focus on energy management at their outer envelopes. However, pursuing this building focused approach alone means that buildings are treated as stand-alone entities with minimal consideration to their impact on the surrounding urban landscape and vice versa. Where urban density is high, individual buildings interact with each other, reducing access to sunshine and daylight, obstructing airflow and raising outdoor air temperature. If/when each building pursues its own sustainability agenda without regard to its urban context, the result will diminish the natural energy resources available to nearby buildings and worsen the outdoor environment generally. This paper examines some of these urban impacts using examples from the City of London where rapid transformation is taking place as very tall buildings with exceptional energy credentials are being inserted into a low-rise city without a plan for the overall impact of urban form. The focus of the paper is on access to sunshine and wind and the wider implications of sustainable strategies that that focuses on individual buildings to the exclusion of the surrounding urban landscape. The work highlights the need for a framework that accounts for the synergistic outcomes that result from the mutual interactions of buildings in urban spaces.     

Aerodynamic interference effects of a proposed taller high‐rise building on wind pressures on existing tall buildings

When a large super high‐rise building taller than the surrounding tall buildings is built in a dense urban area, the aerodynamic interference effects of the surrounding buildings on the proposed building attract much attention, while the interference effects of the taller high‐rise building on the nearby existing buildings are often ignored. Based on a series of wind tunnel tests, the interference effects of a proposed taller high‐rise building, an adjacent equal‐height partner building, and relatively short background buildings on the target building's local wind pressures are analysed in this paper. Two‐dimensional numerical simulation are carried out to further understand the interference mechanism in some cases. The test results show that the influence of a nearby proposed taller high‐rise building may lead to wind‐induced damage on the interfered shorter buildings' envelopes. The envelope structures of other surrounding buildings facing the side of the proposed building need to be given more attention.     

A comparison between CFD and Network models for predicting wind-driven ventilation in buildings

The aim of this paper is to compare the implementation of computational fluid dynamics (CFD) and Network models for airflow rate estimation in buildings. The CFD software used is Fluent 5.5. Comparison between the predicted and simulated airflow rate is suggested as a validation method of the implemented CFD code, while the common practice is to compare CFD outputs to wind tunnel or full-scale measurements. This could be useful for studies that have no access to laboratory or full-scale testing facilities. Results obtained from testing a number of cases have been compared and analysed, considering normal and oblique wind directions. The comparison held between mathematical and CFD results generally showed a good agreement, which seems to justify the use of CFD code for predicting natural ventilation in buildings.     

基于测力天平风洞试验的大跨封闭式输煤栈桥风荷载分析

大跨、高柔结构对风荷载非常敏感,针对此类结构风效应的研究是非常有必要的。基于高频测力天平节段模型风洞试验,测得不同风向角下,封闭式输煤栈桥各典型支撑塔柱及栈桥桥面两个水平向的基底弯矩和剪力。并通过模型基底力平均值计算并分析了各典型支撑塔柱及栈桥桥面体型系数,得到了体型系数随风向角的变化规律。将体型系数试验值与规范值比较,结果表明二者吻合较好,验证了本试验的可靠性,也说明按照规范进行输煤栈桥抗风设计是合理的。分析了周边建筑物对输煤栈桥风荷载的干扰效应,提出了干扰修正系数,为该建筑物基底弯矩和剪力验算以及结构抗风设计提供依据。     

双椭圆形塔楼风荷载特性风洞实验研究

本文通过风洞实验的方法研究了以椭圆形为基本截面形状,两个相邻的由条状平板搭接构成的塔楼建筑风荷载的特性。结果表明,两个相邻的塔楼在一定的风向角下会形成比单个塔楼更大的风荷载。文中根据不同风向角下的风洞实验结果,结合当地的风气象资料,给出了该建筑更加合理的表面饰物风压分布数据。对今后类似的结构设计具有参考价值。同时也说明为了达到安全性和经济性两方面的目的,在作结构设计前对这类外形有较大变化的建筑及其群体间的影响进行适当的风洞实验是十分必要的。