地域气候条件下异型建筑室外风环境绿化改进研究

Research on the improvement of outdoor wind environment greening of special-shapedbuildings under regional climate conditions

为了研究绿化对异型建筑室外风环境的改进效应,本文采用CFD方法和Realizable K-ε湍流模型,结合乌鲁木齐地区风环境特征,以异型建筑新疆大剧院为例,以城市空间中1.5 m人行高度处风速小于5 m/s为评价指标,依据单棵、一排树木周围流场特性的风洞试验和数值模拟对比,对大剧院周围无绿化和现有绿化方案进行分析,并根据树木周围流场特性及对建筑周围风环境的影响提出更为合理的绿化布局,以此满足室外行人舒适度要求。结果表明:树冠处阻风作用最好,随着距树冠距离的增加,阻风作用逐渐降低;树冠两侧及间隔处有导风作用,使得局部风速增大;留有间隔的一排树木在满足经济条件的同时仍能起到优于单棵的阻风效果,更适合实际使用。异型建筑的凹角及拐角处易生成涡流和局部高风速区,在建筑抗风设计时应予以充分考虑。本研究可为利用树木阻风导风和类似异型建筑的室外风环境绿化改进提供参考。

For studying the greening improvement on outdoor wind environment of special-shaped buildings,the research,under the guidance by the CFD method and the Realizable K-εturbulence model combined with the wind environment features of Urumqi,takes the special-shaped building-Xinjiang Grand Theater as the sample to analyze the non and existing afforestation plans of Xinjiang Grand Theater at the wind speed less than 5 m/s in the pedestrian-level of 1.5m in urban space as that by the evaluation indicators and the wind-tunnel experiment and numerical simulation of flow field characteristics around a tree or a row of trees as comparison.It also proposes a more reasonable afforested layout to meet the comfort requirements for outdoor pedestrians based on the flow field characteristics around trees and their influence on wind environment around buildings.The results show that the best wind-guide effect is found at the crown.With the distance from the increasing crown,the performance gradually decreases;the wind-guide effect on both sides of the crown and at its intervals leads to an increase in local wind speed;a spaced row of trees not only satisfies the economic conditions but also produces a better wind-resistance performance than a single tree,which is more suitable for practical use.Vortex and local high wind speed areas are easy to form in concave corners and turnings of special-shaped buildings,which should be fully considered in the wind-resistance design of buildings.This study can provide reference for using trees to resist and guide wind and the greening improvement of outdoor wind environment in similar special-shaped buildings.