The effects of heating and tree configurations on pollutant dispersion and air temperature in Street Canyon

dc.contributor.authorMuhammad Yazid, Muhammad Noor Afiq Witri
dc.date.accessioned2024-12-17T00:20:39Z
dc.date.available2024-12-17T00:20:39Z
dc.date.issued2015
dc.descriptionThesis (PhD. (Mechanical Engineering))
dc.description.abstractDeterioration of outdoor air quality and harsh outdoor microclimate in a street canyon posed a serious threat to the urban dweller’s physical and mental health. The main purpose of this study was to investigate the combined effects of presence of trees, different diurnal heating situations and different street ratios on wind speed, pollutant dispersion and air temperature in a street canyon by means of Computational Fluid Dynamics (CFD). Initially, investigation on the suitability of the existing wind tunnel were carried out. Wind tunnel results shows that the formation of a thick turbulent boundary layer had a good vertical mean velocity profile except for the turbulent intensity profile; hence an alternative wind tunnel study was adopted as benchmark data for CFD. Validation study of numerical simulation of wind flow in a street canyon under the influence of thermal effects shows that the prediction by the large eddy simulation (LES) against wind tunnel data was better than the Reynolds-averaged Navier-Stokes (RANS) at steady state and the unstable RANS (URANS). Qualitative comparison between the parameters that were adopted for parametric study against previous studies were adequately representing a street canyon at full scale. Parametric study shows that the street aspect ratio was identified as the dominant factor compared to the presence of trees in reducing wind speed and air quality in a street canyon because of low momentum transfer from ambient wind into lower region of street canyon. Furthermore, the presence of trees in a street canyon under different diurnal heating situations is an ideal condition to achieve simultaneous low air temperature and better air quality where tree shade can reduce the surface area being heated up by the sun whilst the buoyancy force produced in street canyon by diurnal heating situations can compensate for the wind reduction caused by the trees.
dc.description.sponsorshipFaculty of Mechanical Engineering.
dc.identifier.urihttps://openscience.utm.my/handle/123456789/1468
dc.language.isoen
dc.publisherUniversiti Teknologi Malaysia
dc.subjectMeteorology and climatology
dc.subjectAir pollution
dc.subjectEnvironmental engineering of buildings
dc.subjectUrban forestry
dc.titleThe effects of heating and tree configurations on pollutant dispersion and air temperature in Street Canyon
dc.typeThesis
dc.typeDataset
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CONTOUR PLOT OF MEAN WIND SPEED
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CONTOUR PLOT OF MEAN AIR TEMPERATURE
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C# USER DEFINED FUNCTION FOR THE BOUNDARY AND INITIAL CONDITIONS
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