历史街区中既有建筑风环境模拟及优化设计——以青岛小扬州宾馆为例

历史街区作为历史发展和物质表现的载体,在城市演变中的重要性是不言而喻的。而风环境作为城市微气候中的一个重要方面,对城市整体的空气环境质量和人体舒适度都有着很重要的影响。将风环境与历史街区建筑方案设计相结合,探究历史建筑设计方案中风环境的应用。本研究以青岛市历史街区江苏路小扬州宾馆重建方案为例,基于CFD数值模拟技术,运用PHOENICS软件进行风环境模拟,对方案在冬夏两季主导风速、风向下的风速图、风压图进行分析,得出更适合当地气候的建筑形态。     

高密度街区光环境性能研究

光环境在绿色城市与绿色建筑的建设过程中有着重要的作用,现代城市在快速城市化的背景下出现越来越多的高密度街区。采光环境研究及指标主要针对建筑物内部空间,而很少针对城市外部空间方面进行研究。文章基于Grasshopper平台,对城市高密度街区背景下的建筑外部空间光环境性能与天空开阔度的相关性进行模拟研究。     

城市住区改造前后不同街区形态下的风环境差异——以苏州旧城改造城市切片为例

本文选取了平江历史街区附近的5个城市切片,进行调研建模后,用AIRPAK3.0风环境测试软件将其分别置于相似的风场环境,进行风环境测算,并对其进行对比分析,主要集中在风速和道路、广场、建筑璃度之间的联系上。研究的目的在于发理同样的风场下,不同的建筑布局方式对于风环境的影响,即改造前及利用不同的改造模式改造后的街区形态在相似的大环境下风环境的差异。     

某大型建筑行人风环境数值模拟研究

伴随着我国城市化的进程,各大城市中出现越来越多的大型公共建筑与设施,其建筑周围行人风环境品质越来越引起人们的广泛关注。本文根据气象统计资料,结合当地典型季节风速风向联合频率分布数据,采用计算流体动力学(CFD)中雷诺平均的方法对某大型建筑周围风环境状况进行了详细数值模拟研究。根据数值模拟计算得到该大型建筑在16个方位风向角下周边的速度场分布,并基于大概率发生事件的风环境品质评估标准,按照行人的坐、站立、行走等活动类别舒适性评判标准,对大型建筑周围人员活动密集场所行人高度位置的224个测点的风环境品质进行了评估,通过数值模拟研究和分析,得到具有参考价值的结论。     

传统街区居民环境行为与微气候关键要素关联性分析

人类在外部空间开展的各项行为活动方式受城市微气候影响,研究居民环境行为与微气候关系有利于街区环境品质的提升.文章选择西安小寨传统街区为研究对象,利用ENVI-MET微气候模拟平台获取温度、风速数据,同时采用问卷调查与实地调查方法,观察记录居民环境行为,对比两组数据获得居民行为与微气候内在规律.该研究有利于提升传统住区的环境品值,并且为传统街区空间优化设计提供借鉴意义.     

面向城市设计的行人高度城市风环境评价准则与方法

行人高度城市风环境是城市生态 环境的重要组成部分之一,是绿色城市设计 需要考虑的因素之一。在城市设计阶段进行 科学合理的行人高度城市风环境评价具有 重要的意义。尽管国际上已有多种行人高度 城市风环境评价准则,但均不适用于城市设 计阶段使用。通过对已有研究成果的分析, 建立了基于城市空间分析的行人高度城市风 环境评价准则和方法,综合考虑了机械舒 适度、安全性、风速放大系数、行人对风环 境的主观容忍程度等要素,并提出了处理风 环境特有的随机性的办法。     

影响胶东滨海城市街区微气候的空间形态要素研究

面对当前微气候变化引起的城市街区外部空间环境质量的恶化,本文有针对性地将胶东滨海城市街区形态的和谐循环发展与微气候的制约因素结合在一起,总结胶东滨海城市街区的微气候环境特征,挖掘和提炼胶东滨海城市街区的地形特征、空间结构、建筑布局及开放空间等空间形态要素与微气候风环境的关联因子,并加以分类、梳理、分析、归纳。在尊重、顺应、改善、优化微气候的前提下研究城市滨海街区空间形态建设中的可持续发展问题。     

典型住区形态下的风环境评估——以北京为例

随着城市化进程加快,许多城市环境质量堪忧,风环境的改善可有效地促进空气污染物的扩散降减和抑制城市热岛效应的形成。文章通过城市住区形态参数化研究和CFD模拟来研究风环境和街区形态的耦合关系。选取了北京市10种典型的住区进行城市形态参数化归纳,通过数值模拟,对各组模型在均一化来风初始条件下的不同高度平面的平均风速、湍流强度、2m高度低风速区占比等风环境参数进行了统计分析,发现了一些影响近地面(<20m)风环境的重要的城市形态参数。论文有助于揭示街区形态对城市风环境的影响规律,提出的基于风环境的住区形态规划设计建议,有利于选择合适的街区形态以促进近地面高度的空气污染物降减,为未来城市住区营造良好通风环境提供规划建议和参考。     

基于CFD技术的城市风环境设计策略研究——以重庆市永川区凤凰湖城市设计为例

风环境是城市环境的一个重要组成部分。本文以重庆市永川区凤凰湖城市设计为例,建立适用于城市复杂环境条件下的风场分析模型。基于概率阈值法,对场地风速超越行人舒适阈值的概率进行数值模拟。通过模拟结果分析了场地风环境的特征及其对行人舒适度的影响,并提出相应的场地风环境品质改善策略。希望对未来的城市规划与设计有所帮助。     

截面旋转及朝向对建筑周边行人风环境的影响

基于风洞试验和风环境评估理论对方形、矩形、椭圆形等基本形体及其相应截面旋转形体的超高层建筑周边行人风环境进行研究,分析了不同朝向及不同旋转角度下建筑周边行人风环境的舒适性和安全性。结果表明：朝向变化对方形截面建筑行人风环境影响较小,对矩形及椭圆形等双轴不等长截面建筑影响较大,将短边垂直于主导风向可以显著改善建筑周边行人风环境;截面旋转改变了朝向变化对建筑行人风环境的影响规律,旋转建筑与基本截面建筑的行人风环境分布随朝向的增加呈现相反的变化趋势;截面旋转不利于方形截面建筑周边行人风环境分布;对于矩形和椭圆形截面建筑,截面旋转可以减小朝向的变化对行人风环境的影响。研究成果探明了截面旋转角度及朝向变化对基本形体超高层建筑周边行人风环境的影响规律。     

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.

     

Application of exceedance probability based on wind kinetic energy to evaluate the pedestrian level wind in dense urban areas

In the present study, assessment of wind environment within the pedestrian level domains of highly populated areas is carried out. Three typical models of a dense urban area are considered and numerically simulated in order to examine the effects of the geometry of such models on wind flow characteristics within the pedestrian domain of a street canyon located within this area. The calculated flow fields are employed to estimate the exceedance probabilities within the study domain using a new approach: average wind kinetic energy. The study is applied to Tokyo, Japan; based on its mean wind velocity data. The results demonstrate that the exceedance probability analysis of the pedestrian wind environment could be a valuable tool for assessing urban areas. Also, the calculated probabilities demonstrate substantial dependence on both the geometry of building arrays and the wind conditions of the considered domain.     

温州市灵昆岛区域热环境的模拟初步研究

针对温州瓯江口新区灵昆岛新建规划设计,在城市规划设计阶段分析新建建筑群的热环境变化特征,研究其对周围区域热环境的影响,有效推动灵昆岛城市规划设计进展。应用Sketchup软件建立三维建筑模型,选择合适计算区域,利用PHOENICS计算流体软件进行离散求解并对模拟计算结果进行后处理,分析1.7 m行人高度处的风速和温度,分析区域内热岛效应形成的原因以及热风环境和热环境的分布特征,最后为优化城市区域热环境状况进而改善研究区域内的人居环境,有效降低城市区域建筑能耗提出合理化建议。     

Wind tunnel tests on the dispersion of vehicular pollutants in an urban area

Results are presented from an extensive series of wind tunnel tests to investigate the dispersion of a tracer gas emitted from a ground level source on a 1 : 125th scale model of an urban area typical of those found in the UK. Concentrations of a tracer gas, propane in air, were measured at a number of pedestrian level locations around the model using fast-response flame ionisation detectors. These were supplemented by pedestrian level wind speed measurements using hot-film anemometry. Measurements were made for changes in the wind azimuth angle and for changes to the building geometry. General conclusions were drawn about the relationships between building geometry and the pedestrian level atmospheric environment and a number of simple empirical relationships derived between the changes in the measured wind characteristics and the characteristics of tracer concentration. Both mean and fluctuating wind speeds and concentrations were measured in the experiments and subsequently quantified using a novel empirical method that may potentially be of use to both urban planners and wind tunnel engineers.     

Design for wind comfort in The Netherlands: Procedures,criteria and open research issues

A code for the assessment of wind comfort and wind danger in the built environment in the Netherlands is presented. The code is not another legal building requirement, but a helping hand to include wind comfort in a building programme. It regulates technical procedures and some quality control. A decision scheme indicates which building plans need professional assessment by wind engineers.Local wind speed data are predicted from wind tunnel or CFD simulations. Statistics of a reference wind speed at the building location is needed to calculate the probability that a threshold wind speed is exceeded. The code prescribes a method which is offered as a software package to calculate the statistics of the reference wind speed at a height of 60 m. It includes the most up-to-date data from meteorological stations in the Netherlands.The probability that the pedestrian wind speed exceeds a threshold value of 5 m/s is a measure for wind comfort. Larger probability means less comfort. Therefore, five grades of wind comfort A–E are defined as function of this probability. In addition, for three different activities of the public (traversing, strolling and sitting) these grades of wind comfort are assessed in terms of a poor, moderate or good local wind climate.     

Effects of building height and porosity on pedestrian level wind comfort in a high-density urban built environment

Pedestrian level wind environment is affected by stagnated airflow in high-density cities. This study provides an understanding of the effects of building height and porosity size on pedestrian level wind comfort. The computational fluid dynamics (CFD) technique is utilized to reproduce wind flow around buildings at pedestrian level, and new wind comfort criteria for a low wind environment are adopted to evaluate wind comfort. More specifically, the Steady Reynolds Averaged Navier–Stokes (RANS) renormalization group (RNG) k–ε turbulence model is employed in this study, and the accuracy of the simulation results are assured by validation against the wind tunnel test data. The influence of different building heights and porosity sizes on wind comfort around an isolated building and a group of buildings are subsequently examined. It is shown that an increase building height could improve wind comfort inside the site boundary for both the isolated building and group of buildings. Furthermore, the wind comfort benefits increased when porosity is on the first floor compared to when it is on the second floor. Moreover, larger porosity size generally results in better wind comfort than smaller porosity size. From a practical view point, this study provides information for city planners and architects to use in the improvement of pedestrian level wind comfort, without losing land use efficacy.     

Building mounted wind turbines and their suitability for the urban scale—A review of methods of estimating urban wind resource

In this paper, a review is presented of academic literature regarding urban wind speeds for building mounted wind turbines. Site measurement of wind speed requires time and money that often are not available for small micro-generation projects. Research into wind speed estimation for the urban environment has shown that street canyons affect urban wind flow, that wind speed up over the roof ridge is only evident for isolated single buildings, that the wind resource “seen” by a building mounted wind turbine is affected by positioning (height above roof ridge and position relative to the prevailing wind direction), that urban terrain roughness is high, and that adjacent buildings can cause wind shadow. This multiplicity of factors makes it difficult to generalise a wind resource estimation methodology for the urban environment. Scaling factors may prove to be a practical solution, provided the accuracy of their use is well understood.     

楚河汉街的建筑空间设计评价

现代步行商业街是城市开放空间的一个特殊分支,它从属于城市的人行步道系统,是现代城市空间环境的重要组成部分。楚河汉街因其独特的地理位置以及为市民提供了一个交流、购物、娱乐、休闲的场所而被人们誉为“中国第一个水岸城市步行街”。就现在的楚河汉街来看,在建筑的形式和室外空间的处理上还是存在着一些问题的。因此,本文从研究步行街空间形态特征及商业街中人的行为心理需求着手,对建立符合人的使用需求的步行商业空间的途径和方法进行探讨,从各个角度品评了楚河汉街的设计。同时也对步行商业街环境的发展趋势进行美好的展望,借以说明创造理想步行商业街环境的奋斗目标和方向。     

城市住区室外通风与空气负离子浓度评测研究

选取合肥市东南区域典型居住区为研究对象,运用CFD数值模拟和室外实地观测相结合的研究方法,量化模拟了夏冬两季住区室外环境的风速图,并分析了其模拟通风状况;在此基础上得到了住区内不同环境的通风特征,包括建筑布局、空间形态、建筑密度、交通路网、植物绿化等对通风的影响;再根据模拟参数,在住区内选取样点实地观测了不同环境特征下的住区夏冬两季的空气负离子和风速、温度、相对湿度以及空气正离子等数据,探索了住区室外环境中空气负离子浓度与风速、温度、湿度和空气正离子之间的相关关系。同时进一步整理了近4万个有效数据应用于空气负离子和风速的时空分布研究,推导出夏季风速与空气负离子的线性回归方程,并运用偏相关分析,得出城市住区环境中空气负离子与风速呈极显著负相关,给出了线性回归方程Y=-0.001X-0.003。最后结合建筑布局的组合、开敞空间的设计和线性道路的组织等分析了空气负离子和风速的分布规律,用以说明评价住区室外环境通风状况的可行性,为今后城乡规划和建筑设计提供科学依据和设计思路。     

建成环境对行人安全性和步行性的影响:文献综述和案例分析

为更有效地建设步行社区,提升公共健康水平,拓展对建成环境和行人安全关系的理解十分重要。在系统性文献综述的基础上,归纳了应用广泛的"D指标",全面梳理建成环境对步行性和行人安全性两方面的影响。在案例分析中,通过控制空间自相关,论证了行人安全性与D指标的相关性,指出步行指数对于步行性和行人安全的意义的差异。城市规划师和政策制定者应进一步评估传统意义上的步行友好场所是否给行人提供了足够的安全保障,未来开展促进步行的研究时,应同时考虑提高行人安全的有效途径。