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標題: | CFD 模擬被多棟建築環繞之高層建築物地下室風場分析與改善可行性之研究 CFD modeling of wind field analysis and improvement feasibility of high-rise building basement with multiple buildings surrounded |
作者: | Tung-Cheng Chuang 莊東承 |
指導教授: | 朱錦洲(Chin-Chou Chu) |
共同指導教授: | 張建成(Chien-Cheng Chang) |
關鍵字: | 平均雷諾方程,行人風場,多建築排列,地下室,紊流, RANS,pedestrian wind field,multiple buildings,basement,turbulence, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 近數十年來,由於城市高速擴張,計算流體力學 computational fluid dynamic 逐步完善,且受益於電腦性能高速發展,使得都市建築不再需要進行昂貴的實驗,即可利用數值方法得到風場的物理特性。在此一領域中,多數研究均針對行人風場、室內通風與建築物間之交互作用,當環境風速上升,由於不同建築物之排列,容易在行人風場的高度產生強風,致使地面行人行走困難,或甚至建築物受損,當行人風場之強風順著車道灌入地下室後更會導致人員產生不適,甚至鐵門與 機械 無法正常運作。 本研究 針對主建築物之地下室,在東北季風盛行之季節,探討將產生何種變化,且在建築物四周均已有新的建案在建設,本研究之模型亦將此一因素一併考慮,計算縮流效應之影響。為了逼近現實條件,入流使用都市條件下之指數剖面大氣邊界層,建築物表面與地面設定為無滑移條件,計算域之流體出口分別設置於外流場出口、地下室出口與電梯間。 現今數值模擬已能針對非定常之紊流模型進行計算,各種不同模型包含 DNS、 RANS、 DES與 LES等,各模型均有其側重之優勢與劣勢,本研究採用 −模型 雷諾平均方程 )),在數量龐大的網格下能以較少的資源 進行計算,研究結果表明,進入地下室之流體並非原本行人風場高度之流體,而是來自建築物中間到 3/4 高度之下衝渦流,而在車道上加蓋或是改變地下室內之特定位置之結構,均能使地下室之衝擊壓力與流入地下室之質量流率明顯下降,另研究結果也顯示,在相鄰較近距離之兩棟建築物由於中間流體加速,產生渠化效應 (channel effect),使接近地面之流體向中間移動。 In recent decades, due to the rapid expansion of cities, the preliminary improvement of computational fluid dynamics, and the rapid development of computer performance, urban buildings no longer need to conduct expensive experiments, and the physical characteristics of wind fields can be obtained by numerical methods. In this field, most researches focus on the interaction between pedestrian wind fields, indoor ventilation and buildings. When the environmental wind speed increases, due to the distance between buildings, strong winds are likely to be generated at the height of the pedestrian level, causing people have difficulty walking, or even buildings are damaged. When the strong flows into the basement along the driveway, it will cause discomfort for the people, and even the iron gates and machinery cannot operate functionally. This research is aimed at the basement of the main building. What kind of changes will occur during the northeast monsoon season, and there are already new projects under construction around the building. The model of this research also considers this factor. Calculate the influence of contraction flow effect. In order to approximate the actual conditions, the inlet condition uses the exponential velocity profile of atmospheric boundary layer under urban conditions, the building surface and the ground are set to non-slip conditions, and the fluid outlets of the calculation domain are respectively set at the outer flow field outlet, basement outlet and elevator room. Numerical simulations are now able to calculate unsteady turbulence models. Various models include DNS, RANS, DES and LES. Each model has its own advantages and disadvantages. This study uses the RNG k-ε model (Reynolds average equation), whitch can be calculated with fewer resources under a large number of grids. The results show that the fluid entering the basement is not the fluid at the pedestrian level, but from the down wash flow from the middle of the building to below 3/4 of the building height. Adding a cover on the driveway or changing the structure of a specific location in the basement can significantly reduce the impact pressure of the basement and the mass flow rate into the basement. The results also show that in two adjacent buildings, due to the acceleration of the intermediate fluid, the channel effect occurs, which causes the fluid close to the ground to move to the center. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/67894 |
DOI: | 10.6342/NTU202003465 |
全文授權: | 有償授權 |
顯示於系所單位: | 應用力學研究所 |
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