Experimental Measurement on the Airborne Pollution Dispersion around the Step up Street Canyon in the Turbulent Boundary Layer Cross Flow

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Project title

Code/計畫編號

MOST105-2221-E019-048

Translated Name/計畫中文名

紊流邊界層橫流作用下之氣懸性污染在上揚型街谷之擴散特性實驗

Project Coordinator/計畫主持人

Bao-Shi Shiau

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Harbor and River Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=11881197

Year

2016

Start date/計畫起

01-08-2016

Expected Completion/計畫迄

01-07-2017

Bugetid/研究經費

868千元

ResearchField/研究領域

土木水利工程

"臺灣許多城鎮都市比鄰海岸港口，港區旁建築物櫛次鱗比以及人口密集及工商活動頻繁，各種氣懸性污染源(例如：港口停泊船舶廢氣排放、街道交通工具廢氣排放、建築物空調通風設備與餐飲營業廢氣排放等等)排放後，嚴重影響周遭環境空氣品質。街谷兩側建物不等高，當街谷上風區之建築高度低於下風區建築，橫流越過街谷氣流上揚，稱為上揚型街谷。在基隆港區鄰邊上揚型街谷之街道為常見型式之一。因此為了改善與提升臨港濱海城市生活環境品質，實有必要掌握街道周圍環境之廢氣污染擴散變化特性。本研究計畫以實驗量測研究分析探討氣懸性污染排放後，在上揚型街谷之街道之環境污染濃度分佈變化特性。研究成果將有助於港口城市的空氣污染改善管制策略之擬訂，擁有潔淨之空氣提升生活居住環境品質。本計畫主要係採用實驗方式進行量測及分析研究在海岸港口都市地況之紊流邊界層橫流作用下，氣懸性污染在上揚型街谷之街道擴散特性。計畫之研究將考慮流場雷諾數、排放源之密度福祿數、以及不同上揚高度比例、以及街谷形狀比等無因次參數之效應。實驗量測並分析濃度數據，獲得周遭與建物表面之濃度分佈變化，以及羽昇流擴散特性參數(例如：平均垂直厚度、傳輸速度、捲增速度等)，以及擴散範圍指標(例如水平向與垂直向之延散尺度參數與污染團質心軌跡位置)。" "Many harbors in Taiwan are next to cities or towns. Heavy commercial or civil activities usually exist in the streets and around buildings of city. All sources of airborne pollution like ship chimneys from nearby harbors, traffic pollution in street canyon, and restaurant ventilation waste air from buildings. The asymmetric street canyon is termed as step up canyon when the building located in the downwind direction is higher. The step up canyon type of street nearby the Keelung harbor is usually seen. For assessing environmental airborne pollution impact and to protect air quality of the harbor city having the step up street canyon, it is necessary to understand the dispersion characteristics of the pollution plume around the street canyon. The present project will be performed in wind tunnel to investigate the dispersion characteristics of airborne pollution plume interacting with the step up canyon in a turbulent boundary layer cross flow. The experiments will be conducted with considering the Reynolds number, discharged densimetric Froude number, street canyon width (aspect ratio), and heights of upwind and downwind buildings. Cases with various heights of source, aspect ratio of canyon, and different heights between upwind and downwind buildings will be executed in the experiments to study the airborne pollution concentration and pollution plume dispersion characteristics. The wind tunnel measurements of flow and plume concentration field around the street canyon and buildings will be analyzed to yield the wind flow field, plume characteristics (such as: plume depth, transport speed, and entrainment speed), and pollution dispersion characteristics (e.g., plume trajectory, horizontal and vertical plume dispersion parameters)."

Keyword(s)

上揚型街谷
街谷形狀比
紊流邊界層
氣懸性污染
濃度羽昇流
密度福祿數
延散尺度參數
step up canyon
canyon aspect ratio
turbulent boundary layer
airborne pollution
concentration plume
densimetric Froude number
dispersion parameter

DSpace CRIS

Experimental Measurement on the Airborne Pollution Dispersion around the Step up Street Canyon in the Turbulent Boundary Layer Cross Flow

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