This document investigates the dissipation of pollution flow in urban canyons. It uses CFD software to simulate wind flow through urban blocks at different angles (perpendicular, 45 degrees, 30 degrees) to determine which configuration best dissipates pollution particles. The simulations measure turbulence kinetic energy and dissipation at receptor points in the canyon to understand how particle energy changes. The results indicate that an angle of 30 degrees may be optimal for dissipating pollution in the urban canyon setting. Adjusting the orientation and shape of building blocks could help improve ventilation and reduce trapped particles in the spaces between buildings.
Street design and urban microclimate by Nastaran Shishegarnastaranshishegar
Urban climate is an effective issue on the local and
global climates which is influenced by several factors such
urban morphology and density, the properties of urban surfaces and vegetation cover. The inappropriate using of these factors could change the microclimate of urban areas. Streets as considerable parts of urban open spaces have a significant role in creating the urban microclimates. As street geometry and orientation influence the amount of solar radiation received by street surfaces and also airflow in urban canyons. This paper discusses the current literature and evidence for the effects of street design on the urban microclimate with highlighting the impacts of streets geometry (H/W ratio) and orientation on
airflow and solar access in an urban canyon. Researches
conducted on this term have proved that street’s geometry and orientation are key factors in providing a pleasant microclimate at pedestrian level in an urban canyon.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Morphometry and Hydrology relationship in Lidder valleyShakil Romshoo
Morphometric analysis of the Lidder catchment was carried out using geospatial technique.The analysis revealed that the area has uniform lithology and is structurally permeable. The high drainage density of all
subwatersheds indicate more surface runoff.The morphometric analysis also indicates that the area is more prone to weathering due to very-coarse to coarse drainage texture.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Street design and urban microclimate by Nastaran Shishegarnastaranshishegar
Urban climate is an effective issue on the local and
global climates which is influenced by several factors such
urban morphology and density, the properties of urban surfaces and vegetation cover. The inappropriate using of these factors could change the microclimate of urban areas. Streets as considerable parts of urban open spaces have a significant role in creating the urban microclimates. As street geometry and orientation influence the amount of solar radiation received by street surfaces and also airflow in urban canyons. This paper discusses the current literature and evidence for the effects of street design on the urban microclimate with highlighting the impacts of streets geometry (H/W ratio) and orientation on
airflow and solar access in an urban canyon. Researches
conducted on this term have proved that street’s geometry and orientation are key factors in providing a pleasant microclimate at pedestrian level in an urban canyon.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Morphometry and Hydrology relationship in Lidder valleyShakil Romshoo
Morphometric analysis of the Lidder catchment was carried out using geospatial technique.The analysis revealed that the area has uniform lithology and is structurally permeable. The high drainage density of all
subwatersheds indicate more surface runoff.The morphometric analysis also indicates that the area is more prone to weathering due to very-coarse to coarse drainage texture.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
Impact of Ground Effect on Circulation Controlled Cylindrical SurfacesCSCJournals
Circulation control technology and motion in close proximity to the ground have both shown aerodynamic benefits in the generation of lift. Recent research efforts at West Virginia University have explored the potential of merging the two phenomena, in an attempt to enhance both technologies. This paper initiates this combined effort by experimentally investigating the impact ground effect has on the separation location of a jet blown tangentially over circulation controlled cylindrical surfaces. Previous experimental research on circulation controlled cylinders found an optimal radius of curvature and volumetric flow rate; whose model and optimal findings are built upon by this work through the addition of ground effect analysis by varying the ground height. The experiment investigates some of the variables that individually influence circulation control and ground effect; the variables are the radius of curvature, velocity of the jet, and the height from the ground. Data analysis revealed that for a constant volumetric flow rate and varying the height to radius (h/r) value, there is a large amount of variability in the data, indicating that the proximity of the ground has significant impact on the separation location and consequently influence on the potential lift characteristics. Furthermore, when this flow rate was analyzed, it was found that at an h/r of approximately 4.8, it appears that an optimal h/r occurs, based on the surface pressure and flow separation from the cylinders when not influenced by the ground. The data also found that at both radii, 0.520 and 0.659 inches, showed benefit when tested in close proximity to the ground. The findings demonstrate that there is further enhancement potential of the lift generating capability by uniting the lift enhancement of circulation control methodology with the ground effect flight regime. This effort is a preliminary study of a larger effort to determine if merging the two phenomena indicates a lift enhancement. This model does not have a free stream velocity, and subsequently does not measure lift, however, the findings depicted in this effort indicate that there is potential for enhancement, which is currently being researched by the authors.
Presented by IWMI's Nishadi Eriyagama at training event on the concept and application of maintaining Environmental Flows (EFlows) organized by IWMI in Kathmanu Nepal, on September 29, 2015.
IMFOF II Jornada de innovación y turismo (I parte)PalmaActiva
El IMFOF tiene el placer de invitarte a participar del espacio para el intercambio de ideas, servicios y productos innovadores en los distintos subsectores de pequeñas y medianas empresas que trabajan, de manera directa o indirecta, en el sector turístico.
PROGRAMA JORNADA
9h. Recogida de materiales y credenciales.
9.30h. Ponencia “El turismo que viene: ¿quién, cómo, cuánto y cuándo?” Introduce y modera: Jimmy Pons. Conferenciante y apasionado del mundo de los viajes y la experimentación con los medios sociales y la tecnología. Interviene: Antoni Costa, director del Centro de Conocimiento, Inteligencia e Innovación Turística, INTELITUR.
11h. Refrigerio.
11.30h. Ponencia “Mi hotel en Internet: radiografía del sector y tendencias de mercado” Introduce interviene y modera: Jimmy Pons. Interviene Juanjo Bonnemaison, Presidente ejecutivo de diversos productos hoteleros, entre otros Las Gaviotas Suites Hotel y director de Desarrollo de Negocio de la agencia ATIPIKA TOURISM especializada en e-marketing turístico.
12.30h. Taller de Networking y Fastmeetings entre los asistentes.
14h Clausura de la jornada.
Dirigido a empresarios/as y trabajadores/as por cuenta ajena de las empresas turísticas
직장인은 항상 사직서를 품에 안고 사는 직업이라고 하죠. 그렇지만 이렇다 할 기술도 능력도 없는 나는 겁쟁이, 겁쟁이, 겁쟁이
학원을 갈 시간도, 돈도, 체력도 없으신 분들을 위한 딱 맞춤교육 탑크리에듀가 진행합니다 !! _오라클학원/ 자바학원/ 구로학원/ IT학원/ 탑크리에듀교육센터
PalmaActiva Sesión informativa "Aplicaciones informáticas para emprendedores"PalmaActiva
Sesión informativa para ofrecer información sobre aplicaciones informáticas de gestión empresarial para la mejora de la productividad.
Contenido de la sesión:
- Google, algo más que un buscador.
- Aplicaciones Web de productividad personal.
- Introducción a los ERP.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
Impact of Ground Effect on Circulation Controlled Cylindrical SurfacesCSCJournals
Circulation control technology and motion in close proximity to the ground have both shown aerodynamic benefits in the generation of lift. Recent research efforts at West Virginia University have explored the potential of merging the two phenomena, in an attempt to enhance both technologies. This paper initiates this combined effort by experimentally investigating the impact ground effect has on the separation location of a jet blown tangentially over circulation controlled cylindrical surfaces. Previous experimental research on circulation controlled cylinders found an optimal radius of curvature and volumetric flow rate; whose model and optimal findings are built upon by this work through the addition of ground effect analysis by varying the ground height. The experiment investigates some of the variables that individually influence circulation control and ground effect; the variables are the radius of curvature, velocity of the jet, and the height from the ground. Data analysis revealed that for a constant volumetric flow rate and varying the height to radius (h/r) value, there is a large amount of variability in the data, indicating that the proximity of the ground has significant impact on the separation location and consequently influence on the potential lift characteristics. Furthermore, when this flow rate was analyzed, it was found that at an h/r of approximately 4.8, it appears that an optimal h/r occurs, based on the surface pressure and flow separation from the cylinders when not influenced by the ground. The data also found that at both radii, 0.520 and 0.659 inches, showed benefit when tested in close proximity to the ground. The findings demonstrate that there is further enhancement potential of the lift generating capability by uniting the lift enhancement of circulation control methodology with the ground effect flight regime. This effort is a preliminary study of a larger effort to determine if merging the two phenomena indicates a lift enhancement. This model does not have a free stream velocity, and subsequently does not measure lift, however, the findings depicted in this effort indicate that there is potential for enhancement, which is currently being researched by the authors.
Presented by IWMI's Nishadi Eriyagama at training event on the concept and application of maintaining Environmental Flows (EFlows) organized by IWMI in Kathmanu Nepal, on September 29, 2015.
IMFOF II Jornada de innovación y turismo (I parte)PalmaActiva
El IMFOF tiene el placer de invitarte a participar del espacio para el intercambio de ideas, servicios y productos innovadores en los distintos subsectores de pequeñas y medianas empresas que trabajan, de manera directa o indirecta, en el sector turístico.
PROGRAMA JORNADA
9h. Recogida de materiales y credenciales.
9.30h. Ponencia “El turismo que viene: ¿quién, cómo, cuánto y cuándo?” Introduce y modera: Jimmy Pons. Conferenciante y apasionado del mundo de los viajes y la experimentación con los medios sociales y la tecnología. Interviene: Antoni Costa, director del Centro de Conocimiento, Inteligencia e Innovación Turística, INTELITUR.
11h. Refrigerio.
11.30h. Ponencia “Mi hotel en Internet: radiografía del sector y tendencias de mercado” Introduce interviene y modera: Jimmy Pons. Interviene Juanjo Bonnemaison, Presidente ejecutivo de diversos productos hoteleros, entre otros Las Gaviotas Suites Hotel y director de Desarrollo de Negocio de la agencia ATIPIKA TOURISM especializada en e-marketing turístico.
12.30h. Taller de Networking y Fastmeetings entre los asistentes.
14h Clausura de la jornada.
Dirigido a empresarios/as y trabajadores/as por cuenta ajena de las empresas turísticas
직장인은 항상 사직서를 품에 안고 사는 직업이라고 하죠. 그렇지만 이렇다 할 기술도 능력도 없는 나는 겁쟁이, 겁쟁이, 겁쟁이
학원을 갈 시간도, 돈도, 체력도 없으신 분들을 위한 딱 맞춤교육 탑크리에듀가 진행합니다 !! _오라클학원/ 자바학원/ 구로학원/ IT학원/ 탑크리에듀교육센터
PalmaActiva Sesión informativa "Aplicaciones informáticas para emprendedores"PalmaActiva
Sesión informativa para ofrecer información sobre aplicaciones informáticas de gestión empresarial para la mejora de la productividad.
Contenido de la sesión:
- Google, algo más que un buscador.
- Aplicaciones Web de productividad personal.
- Introducción a los ERP.
Программа «Bon Sens» предназначена для автоматизации управления производственными и бизнес процессами на рекламных предприятиях. Все подробности смотрите в нашей презентации.
Silver too dropped taking after theoretical offering and dull mechanical request. Standard gold (99.5 immaculateness) plunged by Rs415 to close at Rs28,980 per 10 grams from Wednesday's level of Rs29,395. The level not been seen since 11 April 2016.
https://www.jindalbullion.com/editorial/gold-prices-at-seven-month-low
Urban Air Quality Modelling and Simulation: A Case Study of Kolhapur (M.S.), ...IDES Editor
As a consequence of urbanization a phenomenal
surge has been observed in the vehicular population in India,
giving rise to elevated levels of traffic related pollutants like
carbon monoxide, nitrogen oxides, hydrocarbons, and
particulates in Indian urban centers. These pollutants can
have both acute and chronic effects on human health. Thus
air quality management needs immediate attention. Air
quality models simulate the physical and chemical processes
occurring in the atmosphere to estimate the atmospheric
pollutant concentration. A variety of air quality models are
available ranging from simple empirical models to complex
Computational Fluid Dynamic (CFD) models. Air quality
models can be a valuable tool in pollution forecasting, air
quality management, traffic management and urban planning.
This paper evaluates the performance of widely used Danish
Operational Street Pollution Model (OSPM) under Indian
traffic conditions. Comparison between predicted and observed
concentrations was performed using both quantitative and
statistical methods. OSPM was found to perform exceedingly
well for the prediction of particulates whereas NO2 predictions
were poorly predicted.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
APPLYING FIXED BOX MODEL TO PREDICT THE CONCENTRATIONS OF (PM10) IN A PART OF...IAEME Publication
This paper offers the applying of Fixed Box Model to predict the concentration of particulate matter of 10 micrometers (PM10) one of the air pollutants that most commonly affects people's health. The input parameters (area source capacity of PM10, wind speed, mixing height, size of area source) were estimated based on the area source emission inventory results including: road source, mobile source, construction source, industry source and household domestic source in a part of AL-Kut District. This emission inventory project was carried out during five months period from November 2015 to March 2016.
Designing the City According to the Wind: Using WAsP to Minimize the Impacts ...AM Publications
Buildings should provide shelter for human activities. With increasing urbanization and increasing
urban population the cities are forced to grow vertically. This increase in high rise buildings density influences the
outdoor climate especially the wind climate. This paper is focussed on the wind flow patterns around high rise
building complex. Incorporation of wind in design process in an important issue, therefore, the design of a building
should not only focus on the building envelope and on providing good indoor environment, but should also include
the effect of the design on the outdoor environment. The outdoor environment of a building, in particular related to
wind, has received relatively little attention in the Building Physics community. The present paper addresses
architects and planners and focuses on the outdoor wind environment for human comfort first, a literature review on
related wind studies is provided. The relation between wind effects, wind comfort, wind danger and wind climate is
outlined.
Urban Air Quality Modelling and Simulation: A Case Study of Kolhapur (M.S.), ...IDES Editor
As a consequence of urbanization a phenomenal
surge has been observed in the vehicular population in India,
giving rise to elevated levels of traffic related pollutants like
carbon monoxide, nitrogen oxides, hydrocarbons, and
particulates in Indian urban centers. These pollutants can
have both acute and chronic effects on human health. Thus
air quality management needs immediate attention. Air
quality models simulate the physical and chemical processes
occurring in the atmosphere to estimate the atmospheric
pollutant concentration. A variety of air quality models are
available ranging from simple empirical models to complex
Computational Fluid Dynamic (CFD) models. Air quality
models can be a valuable tool in pollution forecasting, air
quality management, traffic management and urban planning.
This paper evaluates the performance of widely used Danish
Operational Street Pollution Model (OSPM) under Indian
traffic conditions. Comparison between predicted and observed
concentrations was performed using both quantitative and
statistical methods. OSPM was found to perform exceedingly
well for the prediction of particulates whereas NO2 predictions
were poorly predicted.
An Experimental Study on Vehicular Emission Dispersion through Single Storied...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
To From Almutairi, SaudDate 21 January 2014Subject A.docxedwardmarivel
To:
From: Almutairi, Saud
Date: 21 January 2014
Subject: Abstracts for In-class Assignment
APA Format:
Marshall, A. (2013, November). Thinking Differently About Transportation: How Ideas Drive What we Build. Future Structure, 10-19.
MLA Format:
Marshall, Alex. “Thinking Differently About Transportation: How Ideas Drive What we Build.” Future Structure Nov. 2013: 10-19. Print.
Informative Abstract:
The white paper cites several examples to illustrate how infrastructure development does not necessarily require large investments or sophisticated technology, but can instead be brought about by thinking differently. For example the Bus Rapid Transport (BRT) utilizes buses and dedicated lanes to deliver a fast surface transportation system similar to underground subways. Another example is bicycle sharing and public plazas, being adopted by major cities across the world. A different approach to tackle the twin problems of car congestion and falling revenues from gas taxes was adopted by Ohio planners when they introduced a pilot project to charge motorists according to miles driven, and not according to fuel consumed. Also notable is the revival of intercity bus travel by the “Chinatown” bus system in Boston. Ethnic Chinese in the city started an extremely low priced transit system by picking up people off the streets instead of from designated bus stations. Through these examples the author tries to show that often complex infrastructure problems can be solved by taking account peoples’ lifestyles and habits, and by evaluating the objectives of a project, rather than by simply spending money to create more infrastructures.
Descriptive Abstract:
Infrastructure and transport problems are faced by every major city in the world, but many cities often solve their problems by approaching the problems differently than by investing large amounts. Some of the solutions adopted by cities require neither high technology nor huge government spending – instead they try to meet their objectives in a different way. City planners and transport officials need to identify the lifestyles of city dwellers in order to understand why a problem has occurred, and then need to evaluate their objectives. This often leads to a more optimal solution, often at a much lower cost but with greater participation from users.
1
From:
To:
Date: 2014/17/04
Subject: Proposal to write a report on the negative impact of construction engineering to the environment.
Introduction
Construction engineering is credited for the growth of infrastructure worldwide. Each day, there are more railroads, buildings, bridges, dams, highways and airports, coming up. The drive of this paper is to offer insight into the unwanted effects that come with growth in infrastructure. It will also encompass research findings into the problem and propose possible solutions.
Background of the problem
While growth and development is welcome, it is paramount to look into the downside of modi ...
Offshore structures are continuously exposed to extremely varying aerodynamic
and hydrodynamic loads. The storm waves and breaking waves may cause significant
impact on coastal and offshore structures such as vertical sea wall, wind turbines,
LNG carriers and submarine pipelines etc. The prediction of the breaking wave
impact pressure is the important aspect in the design of those structures. The breaking
wave forces produce the highest hydrodynamic loads on substructures in shallow
water, predominantly plunging breaking waves. Owing to the complex and transient
nature of the impact forces it requires more details concerning the physics of breaking
waves and nature of wave interaction with those structures.
In this paper, A Piston-type wave generator was incorporated in the
computational domain to generate waves. Flow 3D was used for simulating 3D
numerical wave tank. The desired breaking waves are simulated using the concept of
wave focusing using Flow 3D solver. These waves are made to impinge on the elastic
circular cylinders of different materials such as PVC, timber and concrete by varying
the support conditions such as cantilever, both ends fixed, inclined support with 30º
inclination. The hydrodynamic response and the structural response are analysed and
validated with the experimental literatures. The maximum impact pressure transpired
on the cylinder due to plunging wave impact from numerical simulation is found to be
eight times of the non-breaking waves
SIMULATION OF ATMOSPHERIC POLLUTANTS DISPERSION IN AN URBAN ENVIRONMENTAM Publications
Interest in air pollution investigation of urban environment due to existence of industrial and commercial activities along with vehicular emission and existence of buildings and streets which setup natural barrier for pollutant dispersion in the urban environment has increased. The air pollution modelling is a multidisciplinary subject when the entire cities are taken under consideration where urban planning and geometries are complex which needs a large software packages to be developed like Operational Street Pollution Model (OSPM), California Line Source model (CALINE series) etc. On overviewing various works it can be summarized that the air pollutant dispersion in urban street canyons and all linked phenomenon such as wind flow, pollutant concentrations, temperature distribution etc. generally depend on wind speed and direction, building heights and density, road width, source and intensity of air pollution, meteorological variables like temperature, humidity etc. A unique and surprising case is observed every time on numerous combinations of these factors. The main aim of this study is to simulate the atmospheric pollutant dispersion for given pollutant like carbon monoxide, sulphur dioxide and nitrogen dioxide and given atmospheric conditions like wind speed and direction. Computational Fluid Dynamics (CFD) simulation for analysing the atmospheric pollutant dispersion is done after natural airflow analysis. Volume rendering is done for variables such as phase 2 volume fraction and velocity with resolution as 250 pixels per inch and transparency as 20%. It can be observed that all the three pollutant namely nitrogen dioxide, sulphur dioxide and carbon monoxide the phase 2 volume fraction changes from 0 to 1. The wind velocity changes from 3.395×10-13 m/s to 1.692×102 m/s. The dispersion of pollutants follow the sequence Sulphur dioxide>Carbon monoxide>Nitrogen dioxide.
Effect of Wind Direction through Single Storied Building Model Configurations...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The Journal will bring together leading researchers, engineers and scientists in the domain of interest from around the world. Topics of interest for submission include, but are not limited to:
The role of environmental resources management and ecology into current urban...Talles Di Cunto
Essay suggesting urban management practises based on ecological principles and design, supported by social participation in a habitat of ever-developing sustainability.
Effect of Wind Direction through Double Storied Building Model Configurations...inventionjournals
: Effect of wind direction on plume dispersion around urban buildings has been investigated by physical modelling using arrays of buildings- like obstacles at scale 1:100 in boundary layer wind tunnel for double storied buildings and compared with field data. The particular effect of obstacle width- to - height ratio (S/H) was examined for a fixed obstacle plan area density. Series of experiments have been carried out in which the wind direction varied in steps of 5 for selected orientation of line source at 900 , 95, 100 and 105. Further, from the observation, it was concluded that the maximum lateral concentration shift to upward the wind direction of line source is increased for inline double storied buildings model configuration. It can be concluded, the wind tunnel results showed that concentrations at downwind distances decreased as the wind direction increases (positive values) for measured orientation of line source in inline double storied buildings model configuration. In comparison, experimentally observed σz values are below the field values. They were best fitted with power-law profiles. The non-dimensional concentration for both the field and wind tunnel results of double storied inline buildings configuration seems to be more or less uniform. Values of vertical spread parameters for double storied inline array configuration and field data were followed a similar trend but inline array configuration of double storied buildings model, non-dimensional concentrations were typically twice larger compared to the field data. This is attributed to the fact that the tracer material is quite concentrated in the recirculation region in inline array configuration of the double storied buildings model.
REVIEW OF THE URBAN HEAT ISLAND PHENOMENON ANALYSIS AS AN ADAPTATION TO CLIMA...civej
The modelling of the urban microclimate, in particular the phenomenon of the Urban Heat Island (UHI), is
becoming increasingly essential for city planning and urban design. The phenomenon analysis is
henceforth possible thanks to the increase in computational power, the link between simulation tools and
urban databases, which allow to represent explicitly the characteristics of the urban microclimate and to
better understand its effects, through the analysis and evaluation of the different impacts of the urban
climatic or anthropogenic contributors. However, the choice of the scale of the study depends on the
accuracy of the modelling approaches, the capacities of calculation and the availability and reliability of
the data. The contribution aims to highlight the phenomenon of the UHI based on a bibliographic study of
the latest research on this topic in Maghreb cities and the different strategies for adapting them to climate
change and for improving their resilience.
Civil Engineering and Urban Planning: An International Journal (CiVEJ)civejjour
The modelling of the urban microclimate, in particular the phenomenon of the Urban Heat Island (UHI), is
becoming increasingly essential for city planning and urban design. The phenomenon analysis is
henceforth possible thanks to the increase in computational power, the link between simulation tools and
urban databases, which allow to represent explicitly the characteristics of the urban microclimate and to
better understand its effects, through the analysis and evaluation of the different impacts of the urban
climatic or anthropogenic contributors. However, the choice of the scale of the study depends on the
accuracy of the modelling approaches, the capacities of calculation and the availability and reliability of
the data. The contribution aims to highlight the phenomenon of the UHI based on a bibliographic study of
the latest research on this topic in Maghreb cities and the different strategies for adapting them to climate
change and for improving their resilience.
Mathematical model for an area source and the point source in an urban areaeSAT Journals
Abstract
A Mathematical model has been developed to study the dispersion of pollutants emitted from an area source and the point source on
the boundary in an urban area. The mathematical model has been solved numerically by using the implicit Crank-Nicolson finite
difference method. The results of this model have been analysed for the dispersion of air pollutants in the urban area downwind and
vertical direction for stable and neutral conditions of the atmosphere in the presence of mesoscale wind. The concentration of
pollutants is less in the upwind side of the centre of heat island and more in the downwind side of the centre of heat island in the case
of mesoscale wind when compared to without mesoscale wind. In the case of stable atmospheric condition, the maximum
concentration of pollutants is observed at the ground surface and near the point source on the boundary. Same phenomenon is
observed in neutral atmospheric condition but the magnitude of concentration of pollutants in the neutral atmospheric condition is
comparatively less than that of the stable atmospheric condition.
Index Terms: Point Source, Area Source, Mesoscale wind
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Similar to 20091116_90_1_2004_2006addendasupplement (20)
Mathematical model for an area source and the point
20091116_90_1_2004_2006addendasupplement
1. Advances in Environmental Technology 3 (2015) 113-120
*Corresponding author. Tel: +98-913-7944470
E-mail address: s.h.hosseini@mail.ilam.ac.ir
Advances in Environmental Technology
journal homepage: http://aet.irost.ir
Investigation of dissipation flow in the urban canyon
Seyyed Hossein Hosseini1
*, Amir Hosein Peyman Rad2
, Eslam Kashi3
1
Department of Chemical Engineering, Ilam University, Ilam, Iran
2
Department of Architecture, Ilam University, Ilam, Iran
3
Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran,
Iran
A R T I C L E I N F O A B S T R A C T
Article history:
Received 14 March 2016
Received in revised form
18 June 2016
Accepted 19 June 2016
In regard to wind flow in the cities, obtaining a minimal level of pollution in the
environment is achievable. Different policies have been considered for minimizing
urban pollution such as the attachment and/or reduction of building parts like air-
traps, ceiling forms, and so on. Due to an increase in population in cities and an
increasing need for housing, the construction of high-rise buildings is inevitable.
People are forced to live in high-rise buildings to meet their housing needs and from
lack of urban open spaces. A CFD based software, Envi-met, is used to acquire
knowledge concerning the air pollution surrounding the buildings. In this case, we
can approximate that an angle of 30 degrees, in regard to an urban canyon, is the
best angle to dissipate pollution. Also, in an ideal case with imposed changes in the
form, we could reduce the problem by better navigation of inside wind of urban
canyons into spaces between blocks of buildings that have the capacity to trap the
particles. Finally, it is found that we may be able to have more optimal results for
the dissipation of pollutants by suitable orientation of blocks in regard to the wind
flow.
Keywords:
Pollution
urban block
urban canyons
TKE, CFD
Envi-met
1. Introduction
In a metropolis, the use of high-rise buildings for different
purposes such as residential, office, education,
entertainment, and so on is essential. Therefore, high-rise
buildings are part of everyday urban life. Buildings,
factories, cars, etc. contribute to urban pollution. Cars and
traffic emissions are the principal origin for pollution in big
cities. Although there are many advantages in using
motorized vehicles, urban environments are still affected by
traffic for the most part [1, 2].
For instance, the increase of motorized vehicles in India’s
big cities has led to problems caused by the emissions from
these vehicles, which comprises about 64% of the pollution
in the urban climate [3]. The local wind flow inside urban
canyons is greatly influenced by mechanical turbulence
caused by moving vehicles [4]. Free-flowing traffic causes
more turbulence in the canyon, facilitating more dispersion
of pollution [5]. Urban canyons increase overall air
pollution concentrations at the street level. Yet, due to the
difficulty in characterizing such geometric features over a
regional area, they are rarely included in the evaluation of
population exposures [6].
The air quality in street canyons is of major importance,
since the highest pollution levels are often encountered in
these microenvironments. The canyon effect (reduced
natural ventilation) makes them “hot spots” for particulate
pollution contributing to adverse health effects for the
exposed population [7]. A systematic understanding of
dispersion mechanisms (considering mechanical effects as
well as natural movements of air) along with the impact of
urban roads, streets in the canyons, and crossroads is the
preferred means for the improvement and also reduction of
the effects of vehicular emission. The dissipation made by
vehicle movement along with the natural movements of air
fundamentally lead to the dispersion of vehicular pollution,
particularly at the time when the wind doesn't blow (<1m/s)
2. S.H. Hosseini et al. / Advances in Environmental Technology 3 (2015) 113-120114
[8]. In large cities, the discharge of these pollutants from
streets, intersections, and sidewalks is dependent on the
movement of the local winds. To understand this
phenomenon, understanding the behavior of wind in the
urban environment is essential. An urban canyon results
when a street is flanked by buildings on both sides in a linear
way [9]. The dimensions of urban canyons are defined by a
series of elements including the ratio of the height of the
building to the street width (H/W), where the ratio of
elements (H/W) almost equals one (without any opening in
the walls) or more. In a shallow canyon, this ratio is under
0.5 (H/W< 0.5) while the ratio of (H/W=2) describes a deep
canyon. The length of the canyon (L) defines the length of
the distance between the two main intersections. If (L/H=3),
the urban canyon is short. If (L/H=5), then the urban canyon
is average; if (L/H=7), then the urban canyon is long. If the
buildings on both sides of the canyon have the same height,
then this canyon is called symmetric [10]. An asymmetric
canyon with tall buildings that are in a downwind direction
is called "step up" and the opposite situation is called "step
down". Leeward and windward are important terms when
discussing canyons, where leeward is the upwind side of a
canyon and windward occurs when the urban canyon is
perpendicular to the wind flow. (Figure 1).
Fig. 1. Characteristics of street canyons
The aspect ratio strongly affects the initial flushing
mechanics and subsequent flow regime within the canyon
[11]. Wania et al. [12] studied the particles concentration
and considered H/W as well as the concentration of foliage
in two scenarios of perpendicular and oblique wind. They
found that along with H/W and herbal covering
concentration, the concentration of particles increases and
therefore the quality of air and also the velocity of wind
decreases. Husain and Lee [13] and Oke [14] separately
described three types of wind flow direction as the
functions of building geometry (with the ratio of length to
depth), and the geometry of urban canyon (depth to width)
for perpendicular wind flow (Figure 2). If the distance
between two buildings is sizeable and the height is relatively
short, the flow of air which is without any interaction is
classified as an isolated roughness flow regime [15]. If the
height and distances between blocks is such that they
disturb the fortification and turning chamber (considering
the deviation caused by downward passing of flow
alongside the chamber), then the changes in the amount of
established flow is known as the wake interference flow
(Figure2).
The most circular eddy emerged in the deep narrow urban
canyon. It might be because of the transition of movement
across the cutting layer in the height of the roof. On this
occasion, the majority of the flow enters the deep narrow
canyon of the street in the form of a single eddy in the deep
narrow canyon [16]. This kind of regime is known as the
skimming flow regime (Figure 3).
In this case, the ratio is discussed in various articles. DePaul
and Sheih [17] reported a threshold for symmetric urban
canyons between 1.5 and 2.0 m/s and 1.4 for the proportion
of (H=w). Nakamura and Oke [18] described the same digital
thresholds for the proportion of (H=W).
Fig. 2. Perpendicular flow regimes in urban canyons for different
aspect ratios [13, 14]
Fig. 3. Skimming flow regime [14]
The average vertical exchange of the isolated roughness
flow regime for the urban canyons equals the width of the
3. S.H. Hosseini et al. / Advances in Environmental Technology 3 (2015) 113-120 115
urban canyon. In the set up canyons, the isolated roughness
flow regime is smaller and the average vertical exchange is
0.67 of the canyon width [19]. Yamartino and Weigand as
well as Kastner Klein et al. also reported that if the L/H in
the urban canyons becomes 20, it results in an isolated
roughness flow regime. Hoydysh and Dabberdet reported:
Isolated roughness flow regime in the corners of the
structure in the relatively short canyons, with a horizontal
exchange coefficient from the corners of the structure to
the middle of it, causing a convergence part in the middle
of urban canyon block. Meroney et al. reported that in the
free case, there are unusual eddies in the urban canyons
moving upward permanently. Once the isolated roughness
flow regime in the urban canyon is normal, it impedes
appropriate ventilation of the air, causing pollution to be
trapped [19-22].
In this paper, in order to study the optimal form and to
better dissipate particles from the urban canyons, the
different urban blocks and directions are evaluated by Envi-
met.
2. Methodology
2.1. Searching of perpendicular, 45 and 30 degree air flow
In the first case, the wind was parallel to the longitudinal
direction of the blocks and the Turbulence Kinetic Energy
(TKE) (m²/m³) and dissipation (m3/ m3) were assessed. In
the following circumstance, the angle for the air flow with
the direction of longitudinal direction of the blocks was in
both the 45 and 30 degrees, comprising second and third
scenarios. The reason for the assessment of TKE is to
understand which particles are first affected by convection
created by the sun (being affected by, leading into floating
and convectional status) or by wind flow on the surface,
which induces air movement. So due to this and the
principle of conservation of energy, these particles will
continue moving until their energy is consumed and they
would come into a state of immobility. These particles can
consist of dust, pollutions, etc. The need to assess the
effects of these particles on human health gives rise to
reducing these particles more quickly from the
environment, optimizing parts of a block that might trap
these particles. First, three scenarios were evaluated in
order to realize how each of them works. A simple example
to better understand this issue is throwing two balls with
the same weight and different speeds in the same direction,
so that the impediments are the same. We can simply
conclude that the ball with more speed has more energy
and moves a further distance. In the urban environment, we
realize that if the initial energy, e.g. dust particles, is high, it
can exit the locations that we take into consideration
(Figure 4). On the average, this location is in the middle of
the block.
Fig. 4. Position of receptor
Via the assessment of TKE and dissipation as well as
assessing particles energy changes in these locations, we
can understand which location could provide better
ventilation for the particles. To compute these data, we
take advantage of Envi-met software. For the simulation of
wind flow, the principal context of dissipation of a 3-
dimentional uncompressible non-hydrostatic flow has been
investigated by the Navier–Stoke equation (1c), (1b), and
(1a), [23]
𝜕𝑢
𝜕𝑡
+ 𝑢𝑖
𝜕𝑢
𝜕𝑥 𝑖
= −
𝜕𝑝′
𝜕𝑥
+ 𝐾 𝑚 (
𝜕 2 𝑢
𝜕𝑥 𝑖
2 ) + 𝐹(𝑣 − 𝑣𝑔)-
Su
(1a)
𝜕𝑣
𝜕𝑡
+ 𝑢𝑖
𝜕𝑣
𝜕𝑥 𝑖
= −
𝜕𝑝′
𝜕𝑦
+ 𝐾 𝑚 (
𝜕 2 𝑣
𝜕𝑥 𝑖
2) + 𝐹(𝑢 − 𝑢 𝑔)-
Sv
(1b)
𝜕𝑤
𝜕𝑡
+ 𝑢𝑖
𝜕𝑤
𝜕𝑥𝑖
= −
𝜕𝑝′
𝜕𝑧
+ 𝐾 𝑚 (
𝜕 2 𝑤
𝜕𝑥𝑖
2 ) + 𝑔
𝜃(𝑧)
𝜃𝑟𝑒𝑓(𝑧)
− Sw
(1c)
in which f (=104 sec−1) is the Coriolis parameter, P’ is the
local pressure dissipation, and θ is the temperature
potential on the Z level. The θref resource temperature and
potential θ should be supplied in a 1-dimensional model
parallel to the main model in the average conditions of
meteorology. The density of air in the compressible Navier–
Stokes equation has been deleted and the Boussinesq
approximation is used. This causes an additional force,
where W is the thermal force equation for perpendicular
movement [2]. This model keeps time steps for the model
of mass preserve. Note that the transition and distribution
conditions in the 3-dimension state have been written for
the Einstein accumulation (ui= u,v,w) (i = 1,2,3). To simulate
this process, a 1.5 order flow for the comprehensive model
which is based on the work of Mellor Yamada, two
additional equations for local dissipation (E), and its added
dissipation rate to the model are needed [20].
𝜕𝐸
𝜕𝑡
+ 𝑢𝑖
𝜕𝐸
𝜕𝑥𝑖
= 𝐾𝐸 (
𝜕2
𝐸
𝜕𝑥2
𝑖
) + 𝑃𝑟 − 𝑇ℎ + 𝑄𝐸 − ɛ (2a)
𝜕ɛ
𝜕𝑡
+ 𝑢𝑖
𝜕ɛ
𝜕𝑥𝑖
= 𝐾𝐸 (
𝜕2
ɛ
𝜕𝑥2
𝑖
) + 𝑐1
ɛ
𝐸
𝑃𝑟 − 𝑐3
ɛ
𝐸
𝑇ℎ − 𝑐2
ɛ2
𝐸
+ 𝑄ɛ
(2b)
Pr and Th conditions describe the production and waste of
turbulence energy due to wind break and also thermal
4. S.H. Hosseini et al. / Advances in Environmental Technology 3 (2015) 113-120116
layering. Q and QE are the conditions in the local source for
producing dissipation and waste in the foliage covering:
𝑃𝑟 = 𝐾 𝑚 (
𝜕𝑢𝑖
𝜕𝑥𝑗
+
𝜕𝑢𝑗
𝜕𝑥𝑖
)
𝜕𝑢𝑖
𝜕𝑥𝑗
𝑤𝑖𝑡ℎ 𝑖. 𝑗 = 1.2.3 (3)
𝑇ℎ =
𝑔
𝜃𝑟𝑒𝑓(𝑧)
𝐾ℎ
𝜕𝜃
𝜕𝑧
(4)
But Th>0 under the stable case has been ignored.
The calculation of E is used for the perpendicular transition
coefficient which is equal to the convergence of the used
relations in the dissipation. Although cµ=0.09 and 𝜕𝐸 = 1.00
and 𝜕ɛ =1.3 are used for the simulation of the frontier layer
flow and for the removal of coefficients interchange, the
different clustering of thermal layers and under process of
operations which is used by Sievers et al. and Businger et al.
is needed [25,26].
𝐾 𝑚 = 𝐾ℎ = 𝐾𝑞 = 𝑐 𝜇
𝐸2
𝜖
; 𝐾𝐸 =
𝐾 𝑚
𝜎 𝐸
; 𝐾𝜖
=
𝐾 𝑚
𝜎𝜖
(5)
Considering the data presented in Figure 5, it can be
concluded that TKE at the 30 degree angle is in its maximum
level. In Figure 6, the dissipation of pollution at 90 degree
is at its minimal level.
In Figure 7, the turbulent exchange coefficients show that
the maximum changing rate is at 30 degrees. But it must be
mentioned that this only applies to the building and block
height which are being investigated.
Fig. 5. TKE in 3 scenarios of wind directions
Fig. 6. Dissipation in 3 scenarios of wind directions
Fig. 7. Turbulent exchange coefficients in 3 scenarios of wind
directions.
2-2-The wind velocity in the urban canyon
Nakamura and Oke [18] reported the parallel flow of wind
along the direction of the urban canyon with the possibility
of boosting along the parapets. The friction of urban
parapets slows down the accessibility to the air flow. The
longitude element of speed inside urban canyons is in direct
proportion with the wind velocity (speed) on the roof.
Yamartino and Wiegand present a relation [21] where the
proportion constant is a means for access to the zenith
angle of wind flow.
V = u .cosα (6)
Nakamura and Oke report the linear relations between two
wind speeds. For speeds of more than 5m/s, the formula of
Ucanyon= P.uroof (P is variable between 0.37 to 0.68 and
for symmetric urban canyons, the proportion of H=w equals
one) predicts the magnitude of the speed of U and V equal
to 1.2 H and 0.06 in the depth [18]. The low constant
empirical value of p is gained due to the flow deviation.
According to Figure 8 and Figure 9, it becomes clear that
along with the change in the angle of the wind against the
0
2
4
6
8
10
12
14
16
0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
(m²/m³)
height (m)
E 90
E 45
E 30
0
5
10
15
20
0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
(m3/m3)
height (m)
Eps 90
Eps 45
Eps 30
0
0.5
1
1.5
2
2.5
3
3.5
4
0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
m2/s
height (m)
Km.vert 90
Km.vert 45
Km.vert 30
5. S.H. Hosseini et al. / Advances in Environmental Technology 3 (2015) 113-120 117
longitude axis of the blocks, the wind speed in the
mentioned point between the blocks would increase.
Fig. 8. Wind speed in 3 scenarios of wind directions
Fig. 9. Wind speed in 3 directions
It can be concluded that the best angle for the wind flow on
the face of the building and block is 30 degrees. Although
there are many positive instances in this situation, there are
points which cannot be ventilated and thus cannot evacuate
the pollution. These points are usually at the back of a
building where the wind has lost its energy and therefore
cannot evacuate the particles.
Strategies which could produce enough turbulence in these
critical points can be employed in the following cases:
a. changes in the form of the blocks
b. changes in the height of the buildings
c. exploitation of an additional attached element
2-3-Optimization of blocks with 30 degree wind (changing in
roof).
In order to improve the troubled areas, different strategies
can be applied. For instance, Hoydysh and Griffiths [22]
reported that in the case of single tall buildings, the
longitudinal as well as latitudinal level of density in the area
opposite of the wind was reduced. In addition, a single tall
building is suitable for the reduction of pollution
accumulation. Also, Wedding et al. [26] concluded that a
single tall building could improve the overlap of pollutions
in the windward side of a building when there is a very high
density in the leeward side. Hoydysh and Dabberdt [15]
described the distribution state (dispersion) (designed
density by tracking gases) of the leeward side of buildings in
two cases, even and step down of urban canyons, as almost
the same. So it's practical to have a single tall construction
at a hypothetical site. Nevertheless, all of the constructions
in the overpopulated parts of a city must be considered in
order to accommodate these people in very large housing
developments [19, 18, 29]. Schatzmann, Rafailidis et al.
have investigated the effects of the form of the roof on the
dispersion of pollution in the urban canyons. They reported
that in the urban canyons, a step roof has more effect on
the dispersion than a flat one. The reduction of the parts of
forms increased TKE and decreased dissipation [30,31,32].
In order to modify the form of urban blocks in accordance
with previous studies, the following form was created
(Figure 10, 11).
Fig. 10. Change in the roof form (30-1)
The high density of tracking gas in the mid-block shows that
on the leeward sides of buildings, the lack of convergence
in the state of step up canyons can be observed. Of course
the 180 degree rotation of the forms for the optimization of
TKE was a strategy which was assessed as well (Figure 11).
0
5
10
15
20
25 0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
m/s
height (m)
wSpeed 90
wSpeed 45
wSpeed 30
6. S.H. Hosseini et al. / Advances in Environmental Technology 3 (2015) 113-120118
Fig. 11. Other orientations of blocks (up:30-2, down:30-3)
3.Results and discussion
According to Figures 12-15, these three cases have been
compared with each other. In the case of 30-1 in Figure 12,
it has a minimum amount of TKE between the blocks. The
particles dispersion in the back of the block and on the
windward leeward increases the storage of pollution that
causes the wind to adversely affect the block facing the
wind.
Fig. 12. Three scenarios for change in the form of the block
Fig. 13.TKE in 3 scenarios of change in the form of the block
Fig. 14. Dissipation in 3 scenarios of change in the form of the
block
Fig. 15. Wind speed in 3 scenarios of change in the form of the
bloc
In order to compare 30-2 and 30-3, we have a difficult path
ahead. These two cases have similar consequences. To
compare these two cases, another methodology can be
considered. Along the direction of the urban canyon center
(between blocks), we established a line as a criterion to
compare all the existing data with each other. Supposing
0
2
4
6
8
10
12
14
16
18
0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
m²/m³
height (m)
E 30-1
E 30-2
E 30-3
E 30
0
5
10
15
20
0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
(m3/m3)
height (m)
Eps 30-1
Eps 30-2
Eps 30-3
Eps 30
2.5
3.5
4.5
5.5
6.5
7.5
0.25
1.25
2.25
3.25
4.25
5.25
6.25
7.25
8.35
9.69
11.3
13.25
15.62
18.48
21.94
m/s
height (m)
wSpeed 30-1
wSpeed 30-2
wSpeed 30-3
wSpeed 30
7. S.H. Hosseini et al. / Advances in Environmental Technology 3 (2015) 113-120 119
that 30-3 is a criteria case and 30-2 is a variable one, Figure
16 displays the consequences; it can be observed that from
the place where the urban canyons start till their ending
point, our horizontal exchange coefficient increases.
Particles in the 3-30 case were evacuated and removed
better than the 30-2 one. Of course, the fastest wind speed
according to Figure 16 belonged to the 3-30 case. Perhaps
it can be concluded that better navigation of wind as well as
a speed increase among blocks caused such optimization.
To realize an environment free of pollution with
optimization of air in the urban environments, the blocks
form could be changed to achieve a more uniform
dispersion of clean air without pollutions.
Fig 16. Comparison between 30-3/30-2
4. Conclusions
It was shown that the interactions between wind direction,
urban blocks, and the atmosphere inside the urban
environment are complex and can produce a distinct
pattern of different flows and temperature fields. Even
small changes in a building can cause a surprisingly wide
range of different aspects of local climate even if we restrict
our discussion to flow and temperature. The prognostic
calculation over a range of several hours can reproduce
more typical microclimate phenomena than a steady-state
simulation. Due to the slow heat transfer inside the soil,
local surface temperature and humidity are a function of
different exchange and radiation conditions give or take the
last few hours. These effects cannot be reproduced with a
steady-state simulation by just ‘observing a small time
frame of the diurnal cycle. The presented case study proves
that it is not possible to make a statement about the effects
of changes in a complex system like the urban boundary
layer at first glance. Based on the simulation results, the
following main points were made:
1- The best angle of wind flow is 30 degrees that
cleans the air pollution.
2- The dispersion of the particles in the urban canyon
can be optimized by changing the roof of the
building and block.
3- The best urban block form is 30-3 that also can
minimize the air pollution.
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