植栽與建築物配置對風環境之影響

An Investigation into the Tree and Layouts of Building on the Effects of Wind Environment The Public Sector and the Localization Process in the 1950s-1960s

近年來氣候變化劇烈引起人類對環境的關注，各國學者多年來對氣候變化因素進行研究已有成果，如1833年Luke Howard首先提出都市溫度高於週邊郊區溫度研究等。影響都市氣候之因素眾多，包含密集的建築物、都市中綠地、空氣汙染物等，本研究針對植栽結構(孔隙率、樹型、植栽樹冠層與植栽高度比)、植栽與建築物配置關係對風環境之影響進行探討。研究方式首先利用實際測量回饋修正CFD數值模擬設定，再進行各項變因分析。綜合研究結果顯示，風場因建築物阻擋作用形成的渦漩及逆向流對建築物與植栽帶之間的區域變化影響複雜，其中擋風成效以散形樹冠最佳，孔隙率越小(植栽枝葉密度越高)，擋風成效越佳的趨勢，而孔隙率大(0.9)之植栽結構，有利逆向流穿透，增加風速削減作用擋風效果佳，此外植栽樹冠層高度與植栽高度比例為2/3，具最佳擋風效果。

In recent years dramatic change in our climate has focused attention on environmental protection. Various scholars have made significant findings regarding the cause of climate change, in 1833 Luke Howard was the first to study the assumption that the temperature in the city is higher than that of its suburbs. There are many factors that impact the climate within an urban area, including the high density of architecture, the ratio of green space within the city, the level of air pollution and so on. This study focuses on horticultural structure (including porosity, layout, the type, the canopy and height of trees), the relative layout between flora and buildings and its impact on environment. The research method uses actual measurements to feedback and amends the Computational Fluid Dynamics (CFD) setting, then analyzes the various factors. The results of this study show that the vortex and backward flow caused by architecture in the wind field has a complex impact on the aerial change between buildings and vegetation, in which umbrella crowns are the most effective at keeping the wind out; and that the smaller the porosity structure of vegetation the easier it is for backward flow to penetrate, which in turn increases the reduction of wind speed, and therefore is more effective as well. In addition, the ratio between the height of the tree crowns and height of vegetation should be 2/3, to achieve the best wind shield effects.