Spatial distributions of gaseous pollutants CO, NOx, and SO2 in a street canyon in Fung-Shan, Kaohsiung County were measured. The street runs west-to-east with two lanes in a single direction: traffic flows only from west to east. The street canyon is 60 m long (= L) and 20 m wide (= W). The heights of the five-story buildings on both sides of the street are about 16 m (= H). Therefore, the street canyon has an aspect ratio AR (= H/W) = 0.8, and a length to width ratio L/H = 3. Air was sampled on site on three consecutive days, 3 September to 5 September, in 2003. The sampling period were 20 h long, from 00:00 to 19:00 on September 4, but covered only the two rush hours, 07:00-10:00 and 16:30-20:00, on the other two days. Traffic emissions were also estimated using available emission factors from TANEEB (1992). Results show that motorcycles are dominant vehicle in the street. Emission estimations indicate that motorcycle contributed to about 75% of CO emission, automobiles contributed about 80% of NOx emissions, while motorcycles and automobiles each contributed about 50% of SO2 emissions. Variations of traffic emissions generally follow traffic flow rates, indicating reasonable estimations of traffic emissions. When wind blows perpendicularly to the street canyon, air pollutants tend to accumulate in the leeward side. For example, concentration of CO in the leeward side is about two times that in the windward side. Generally, concentrations of air pollutants decrease with height, about 10% to 20% reduction in concentration, particularly noticeable in the leeward side. Results also show that, on leeward side, concentrations of air pollutants in the corridor were lower than those outside the corridor, being about 53.3% difference in CO concentration. However, on windward side, concentrations of air pollutants in the corridor were higher than those outside the corridor, being about 100% difference in NO2 concentration. Keywords: Street Canyon, Mobile Sources, Air Quality, Emission Factor.

In this study, Three-dimensional (3D) airflow and dispersion of pollutants were modeled under various excess wall temperature and traffic rate using the RNG k-£` turbulence model and Boussinesq approximation, which was solved numerically using the finite volume method. The street canyon is 60 m long (=L) and 20 m wide (=W). The height of five-story buildings on both sides of the street are about 16 m (=H). Hence, the street canyon has an aspect ratio (AR=H/W) of 0.8 and a length to width ratio of 3 (=L/W). Vehicle emissions were estimated from the measured traffic flow rates and modeled as banded line sources. 3D simulations reveal that the vortex line, joining the centers of cross-sectional vortices of the street canyon, meanders between street buildings. Notably, there is also a horizontal vortex within street canyon. Pollutant concentrations decline as the height increases, and are higher on the leeward side than on the windward side. The ratio of CO pollutants between leeward side and windward side is related to wind velocity. As wind smaller than 0.7 m/sec , the ratio is 1.23¡Fhowever, the ratio is 2.03 with more wind speed above 1.2 m/sec. The CO concentration reveals that the predicted values generally follow the hourly zigzag traffic rate, indicating that CO is closely related to the traffic emissions in a street canyon. The 3D airflow in the street canyon is dominated by both wind fields on buildings top and street exit. The 3D simulations reveal that air flux is 50% higher than 2D. Entrainment of outside air reduces pollutant concentrations, thus reducing concentrations of CO¡BNOx¡Band SO2 by about 51%¡B68% and 70% ,respectively. Thermal boundary layers are very thin. Entrainment of outside air increases and pollutant concentration decreases with increasing heating condition. For T = 5 K, the upward velocity on leeward side increases by about 10%, Also, the downward velocity on windward side decreases by about 28 %. Furthermore, simulation showed that the averaged inflow speed in the lateral direction increases by about 100% as compared with T = 0 K. Hence, the pollutant concentrations with T = 5 K is ony 50% of those without heating. Simulations are followed measurements in street canyon. The averaged simulated concentrations with no heating conditions are about 11~24% and 22~36% lower than measured for CO and NOx , respectively. For heating conditions and without outside traffic source, the averaged simulated concentrations with T = 2 K are 29~36% lower than the measurements. Even at T = 5 K , the concentrations are only about 54% of those without heating, due to the fact that pollutant dilution is enhanced by buoyancy force as to having more outside air entrained into the canyon. However, when traffic emissions outside two ends of canyon were considered, the simulated CO concentrations are 23% and 19% higher than those without outside traffic sources at T = 0 K and T = 2 K, respectively. Traffic-produced turbulence (TPT) enhances the turbulent kinetic energy and the mixing of temperature and admixtures in the canyon. Although the simulated means with the TPT effect are in better agreement with the measured means than those without the TPT effect, the average reduction of CO concentration by the TPT is only about 5% at a given height and heating conditions. Factors affecting the variations between this work and other studies are addressed and explained.

This thesis analyzes the characteristics of flow pattern and vehicle-emitted pollutant dispersion in roughness surface layer. In an urban environment, wind flow and transported-pollutant source interfere strongly with buildings and other roughness elements on the surface ground, which results in complex characteristics of flow pattern and pollutant dispersion in 3D circumstances. The present study intends to simplify the research domain and investigate the fundamental modeling problems that exist in the field. The current physical research topic is restricted to 2D street canyon in equilibrium conditions. The study is motivated by the fact that characteristics of flow pattern and pollutant distribution inside street canyons are important for public health. The research has applied the computational fluid dynamics (CFD) methodology. To date, insights have typically focused on idealized street canyons without strictly limited boundary conditions and turbulence models. Those approaches face challenges related to their applicability to real urban scenarios or the reliability of prediction results. The thesis examines the influence of grid density, turbulence models and turbulent Schmidt number on pollutant distribution at windward and leeward surfaces of street canyon. Since numerical results usually are validated with wind-tunnel measurement data, the results between full-size model and wind-tunnel model are compared in order to test the Reynolds number effect. The lack of measurement data means that the morphometric method is used to generate upcoming wind profile, including the mean vertical velocity and turbulence parameters. The thesis also analyzes the potential errors brought by the method (Scenario A). Based on the evaluated numerical model, the thesis continues to study the impacts of surrounding buildings and geometry of street canyon on flow and pollutant distribution inside street canyons. The effect of wind on pollutant distribution inside street canyons was also investigated (Scenario A). Furthermore, the influence of roof shape and configuration of street canyon on characteristics of flow and pollutant distribution is also systematically studied, with the results shown in scenario B. The main conclusions of the thesis are that the uncertainty of numerical results derives from different aspects. Wind profile in the inlet profile generated by morphometric method brings major error to the simulation results. Current turbulence models cannot compromise the simulation results between flow field and pollutant distribution field. Ignored small-scale obstacles also need to be handled carefully. Numerical results revealed that flow and pollutant distribution inside street canyons are mainly dominated by the geometry of the street canyon itself. Medium-spaced surrounding buildings are also better able to transport pollutant out of the street canyon. Through systematic analysis, roof shape is proven to have a significant effect on flow and pollutant distribution inside a street canyon. The major impact is altered turbulence intensity depth and strength of shear layer inside the street canyon, which is important for pollutant removal process out of the street canyon. In the future, advanced turbulence models accompanied by small-obstacle effect models need to be developed in order to reliably simulate flow and pollutant dispersion simultaneously. Based on the advanced turbulence model, simulation of flow and pollutant dispersion in a complex 3D environment is essential in the next steps for the purpose of engineering application. Accurate vertical wind profile provided for inlet profile is another interesting direction for further development. Keywords: Flow; Pollutant dispersion; CFD; Street canyon; Reliability / <p>QC 20130215</p>

Turbulent flow inside a street canyon was investigated in an open circuit wind tunnel and in a blow-down wind channel. Two geometries were used for comparison purposes: buildings with pitched roofs and with flat roofs. Both generate the flow of a different category, so the induced ventilation regimes are fundamentally different. Quadrant, Fourier and Wavelet analysis, Proper Orthogonal Decomposition (POD) and vortex detection methods are used to identify coherent structures in the flow and establish their impact on the ventilation of pollution. Two types of the organised motions are detected: the compact areas of sweep and ejection with the scale comparable to the size of building and the small vortices generated in the shear layer behind the building roof. POD identifies the most dominant modes with high coherency in the flow and evaluates the relative contributions of each mode to the overall kinetic energy of turbulence. Rigorous analysis of the correctness of the physical interpretation for such a decomposition is carried out. Wavelet analysis is applied to the time-series of the POD expansion coefficients in order to reveal control mechanism of the dynamics of the modes. Vorticity, calculated from the original velocity data, is decomposed by POD as well. Finally, the correlation between the vorticity...

L’interaction des phénomènes de transfert de chaleur et de masse dans un tissu urbain avec les apports anthropiques participent à l’îlot de chaleur urbain et à la dégradation de la performance énergétique des bâtiments. L’objectif de cette étude est de définir l’impact de la modification des propriétés radiatives aux façades des bâtiments qui peut être réalisée par l’utilisation de revêtements sélectifs colorés récemment développés pour les toitures. Les flux sensibles et l’impact sur les bâtiments sont étudiés pour une morphologie caractéristique des milieux urbains denses, la rue canyon. Un suivi expérimental mené sur des surfaces élémentaires de propriétés radiatives différentes nous a permis de développer par une méthode d’optimisation un procédé de détermination simultané du coefficient de convection et des absorptivités solaires effectives sur la période de mesure. L’utilisation de peintures sélectives dans la configuration canyon retenue est ensuite analysée expérimentalement. Pour cela une maquette (1/10ème) de scène urbaine a été conçue sur la base de 5 rangées de cuves de béton creux qui ont fait l’objet de mesures de températures et de flux radiatifs. Dans un premier temps, le traitement de deux mois de mesures a permis de caractériser les évolutions de champs de températures liés à cette forme urbaine. Par la suite, trois configurations de propriétés radiatives aux façades ont été étudiées simultanément et ont permis d’analyser les modifications spécifiques sur les champs de température, de sur-faces et d’air. Afin d’estimer les économies d’énergie réalisables sur un bâtiment réel ainsi que l’impact sur son environnement proche, une étude paramétrique des revêtements de façade et de la chaussée a été effectuée par des simulations de l’interaction du bâti et du micro-climat. Les méthodes et expériences établies dans cette étude nous permettent d’envisager le développement du traitement des façades et de la caractérisation de leurs performances globales. / Modified heat and mass transfer in the urban built and anthropogenic loads contribute to the urban heat island phenomenon as to the deterioration of building energy efficiency. The scope of this study is to define the impact implied by the modification of façade radiative properties that can be achieved by using selective cool-coloured coatings initially developed for roofing. Sensible heat transfers and consequences on building comfort are studied through a characteristic morphology from dense urban environment, the street canyon. Monitoring of surface energy budget on elementary discs of different radiative properties allowed us to develop, through optimisation method, a process to determine simultaneously the effective solar absorptivities and a convective heat transfer coefficient on the measurement period. The following step consists in an experimental analysis of cool selective paints in the chosen canyon configuration. A reduced-scale model (1/10th) of an urban scene has been designed with 5 rows of hollow concrete tanks that had temperatures and radiative fluxes monitored. Measured data for uniform coatings allowed highlighting the temperature evolution linked to the particular urban form. Afterwards, three façades radiative properties configurations have been studied simultaneously and allowed the analysis of those specific modifications on air and surface temperature fields. Lastly, in order to estimate energy consumption savings on real scale buildings as well as the impact on the near urban environment, a parametric study on coating of façades and roads has been performed through simulation taking into account interactive heat transfers between the built environment and the microclimate. The experiments and methods designed along the study permit to consider façade coating development and global efficiency characterization.

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-03-23T13:25:54Z No. of bitstreams: 1 L?GIA PARREIRA MUNIZ G?AL.pdf: 5270981 bytes, checksum: 96b0646b01e474b8307ad43548bce884 (MD5) / Made available in DSpace on 2017-03-23T13:25:54Z (GMT). No. of bitstreams: 1 L?GIA PARREIRA MUNIZ G?AL.pdf: 5270981 bytes, checksum: 96b0646b01e474b8307ad43548bce884 (MD5) Previous issue date: 2017-02-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The formation of cities has shaped the urban street canyons, defined by the street and the buildings that extend along its sides. The land use and occupation are agents that modify the climate, however this is rarely considered in the urban planning of cities. Aspects like height and width ratio, sky view factor, albedo of the surface materials and the presence of vegetation in the canyon have been widely studied in association with the local climatic behavior. Understanding the influence of these parameters on the microclimate of urban street canyons is indispensable to achieve sustainability between urban occupation and thermal comfort. Therefore, the objective of this thesis is to investigate the interference of land use and occupation legislation and urban geometry in the microclimate of an urban street canyon in Campinas/ SP. The methodology used involves the climatic monitoring of the study area in Cambu? (neighborhood), the urban and climatic characterization of three points with different land use and occupation configurations and the selection of the canyon used for simulation scenarios. These scenarios involve two main aspects: the local urban legislation and the canyon geometry (height width ratio - H/W and length height ratio - L/H). The simulations were performed using the microclimatic simulation model ENVI-met 4.0 preview. Scenarios in agreement with the local legislation showed that, in winter, only 25% of day perceived discomfort to heat. In the other hand, in the summer period, a comfortable feeling was perceived in only 25% of the day, providing discomfort to the heat for the rest of the day. In the scenarios varying the urban geometry it was verified that, for scenarios with the same H/W ratio, the PET (Physiological Equivalent Temperature) value did not suffer significant alteration. However, when the L/H ratio was fixed and the H/W ratio varied, we noted that deeper canyons led to lower PET peaks. The scenario A, for example, with a lower H/W ratio (0.5) and lower L/H (3) ratio, showed PET peak 7.3?C higher than the scenario I with a higher H/W ratio (2.0) and higher L/H ratio (7). The results showed that there is a strong correlation between the H/W ratio and the thermal comfort of the urban street canyons: deeper canyons yield lower PET values. Moreover, it was verified that the climatic conditions of the canyon are independent of their length (L/H ratio) and that canyons oriented in the prevailing wind direction (SE) reached lower PET values. Finally, it was evidenced that shading and wind speed are fundamental in determining comfort in urban street canyons. / A forma??o das cidades tem configurado os chamados c?nions urbanos, definidos pela interface composta pela via e as edifica??es que se estendem em suas laterais. O uso e ocupa??o do solo s?o agentes modificadores do clima e, no entanto, este ?ltimo tem sido pouco levado em considera??o no planejamento urbano dos munic?pios. Entretanto, aspectos como a rela??o altura e largura do c?nion, o fator de vis?o do c?u, o albedo dos materiais de superf?cie e a presen?a de vegeta??o no c?nion t?m sido amplamente estudados em associa??o com o comportamento clim?tico local. Neste contexto, entender a influ?ncia desses par?metros no microclima de c?nions urbanos ? de fundamental import?ncia para se atingir a sustentabilidade entre ocupa??o urbana e conforto t?rmico. Em vista disso, o objetivo deste trabalho ? analisar a interfer?ncia da legisla??o de uso e ocupa??o do solo e da geometria urbana no microclima de um c?nion urbano da cidade de Campinas/ SP. Para isso foi utilizada uma metodologia que envolve o monitoramento clim?tico do recorte de estudo selecionado no bairro Cambu?, a caracteriza??o urbana e clim?tica de tr?s pontos com diferentes configura??es de uso e ocupa??o do solo e a escolha do c?nion de interesse para simula??o de cen?rios que envolvem dois aspectos principais: a legisla??o urban?stica local e a geometria do c?nion (rela??o altura largura ? H/W e rela??o comprimento altura ? L/H). As simula??es foram realizadas com o modelo de simula??o microclim?tica ENVI-met 4.0 preview. Nos cen?rios respeitando a legisla??o o desconforto para o calor foi observado em apenas 25% do dia no per?odo de inverno; j? no per?odo de ver?o a sensa??o de conforto foi obtida em apenas 25% do dia, sendo observado desconforto para o calor no restante do dia. Nos cen?rios variando a geometria urbana verificou-se que, para cen?rios de mesma rela??o H/W, o valor do PET (Physiological Equivalent Temperature) n?o sofreu altera??o significativa. J? quando se fixou a rela??o L/H e variou-se a rela??o H/W, ficou claro que c?nions mais profundos levaram a picos de PET mais baixos. O cen?rio A, por exemplo, de menor rela??o H/W (0,5) e menor rela??o L/H (3), apresentou pico de PET 7,3?C mais alto que o cen?rio I, de maior rela??o H/W (2,0) e maior rela??o L/H (7). Os resultados mostraram que existe forte correla??o entre a rela??o H/W e o conforto t?rmico dos c?nions urbanos: quanto mais profundo, menores os valores de pico do ?ndice PET. Al?m disso, verificou-se que c?nions orientados na dire??o predominante dos ventos alcan?aram valores de PET mais baixos. Por fim, foi evidenciado que o sombreamento da superf?cie e a intensidade da velocidade do vento s?o fundamentais na determina??o do conforto t?rmico em c?nions urbanos.

Title: Urban Ventilation Dependence on Geometric Configuration Author: RNDr. Ing. Libor Kukačka Department: Department of Atmospheric Physics Supervisor: prof. RNDr. Zbyněk Jaňour, DrSc., Academy of Sciences of the Czech Republic, Institute of Thermomechanics, v. v. i. Abstract: The main goal of the thesis is to investigate the impact of urban geometry on the urban ventilation using wind-tunnel modelling. To measure the pollutant transport, both advective and turbulent, within complex urban geometries with a high temporal resolution a special measurement method was developed. At first, the pollution of a simplified urban area was simulated by a ground-level point source and the ventilation of the intersection with respect to four wind directions was studied. Later, the pollution of other simplified and complex urban areas was simulated by a ground-level line source and the ventilation of three different street canyons with respect to wind direction perpendicular and oblique to their along-canyon axis was investigated. The clear impact of urban complexity and wind direction on street canyon ventilation is demonstrated at lateral and top openings of all investigated canyons and the intersection. Whilst the dominance of the pollutant advection is demonstrated at the eaves of pitched roofs, at the roof ridges...