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研究生:呂政忠
研究生(外文):Lu, Cheng-Chung
論文名稱:街谷中溫昇效應對汙染擴散之研究
論文名稱(外文):Buoyant Effect to The Pollutants Transport in Street Canyons
指導教授:陳俊成陳俊成引用關係
指導教授(外文):Chen,Jyun-Chen Luke
學位類別:碩士
校院名稱:淡江大學
系所名稱:水資源及環境工程學系
學門:工程學門
學類:環境工程學類
論文種類:學術論文
論文出版年:1996
畢業學年度:84
語文別:中文
論文頁數:106
中文關鍵詞:街谷溫昇汙染擴散
外文關鍵詞:Street CanyonsBuoyantPollutants Transport
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本研究主要模擬一氧化碳於不同街道高寬比、大氣穩定度、溫昇效應
及交通流量下之擴散情況。並企圖利用此模擬結果以建立行人之污染暴露
量及進一步建立室內與都市街道間之關係。在此研究考慮了幾種影響污染
物於街道中擴散之因子,其包含不同比例之街道高寬比、大氣穩定度、溫
昇效應及交通流量之影響。模擬範圍包含區近都市郊區及都會區,其中考
慮到影響因子及邊界條件。結果顯示當於某些街道高寬比產生兩個渦漩時
,污染物將會嚴重的累積於近地表處。通常污染物累積於第二個渦漩所產
生之停滯區,其會降低污染物之傳輸,進而累積於這些區域中。溫昇效應
之加入將使第二個渦漩比不考慮溫昇效應下於較小之街道高寬比產生。溫
昇效應亦改變了污染物於街道中之擴散模式。於此,行人在不同交通流量
及大氣穩定度下街谷中之污染暴露量將被建立。此研究之結論為污染物於
街道中之擴散主要由於不同之街道高寬比,其較溫昇效應及大氣穩定度之
影響來得大。在某些特殊狀況下,近地表附近 3m 之範圍污染物濃度將相
當之高,其對於街道上之行人將產生嚴重之影響。這些特殊狀況亦於此研
究中發現到。
Carbon monoxide distribution in street canyons under
various geometry''s,atmospheric stability, temperature gradient
induced buoyant effect and trafficload were simulated. We
intend to use the simulation results to evaluatepedestrian
pollutant exposure and to provide external conditions
forevaluating indoor air quality of the buildings beside urban
street. In thisstudy, we consider several factors those may
affect the pollutant distributionin street canyons. The
considered factors include geometry of the streetcanyons,
atmospheric stability, traffic load and turbulent buoyant
effect. Atwo-dimensional domain that includes suburban
roughness and urban streetcanyons was considered as the
simulation domain. The considered influentialfactors were
imposed into the simulation through the associated
boundaryconditions. The simulated results show that serious
pollutant accumulationoccurred at where double vortices
encountered and the situation only occurredat specific aspect
ratios of the street canyons. Usually, the stagnation
zoneformed at where the encounter of two vortices that reduce
the transport ofpollutant and the pollutant tent to accumulate
at the region. Buoyant effectto the vortices formation was
found that the double vortices occurred atsmaller aspect
ratio of the canyons with buoyancy than those without buoyancy.
The buoyant effect also change the pollutant transport pattern
in the canyons.The pedestrian exposure to the street air
pollutant under various trafficloads and atmospheric stability
were evaluated. This study concluded that thepatterns of
pollutant distribution in different street canyons are
mostlyaffected by their aspect ratios where the affect of
buoyancy and atmosphericstability played less role. The
pedestrian exposure to the street airpollution is considered
to be serious under specific conditions when
pollutantconcentrations at 3 m above ground level are very
high. Those specificconditions were also found in this study.
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