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Received: 2022/07/27 | Accepted: 2022/10/28 | Published: 2022/11/1
Received: 2022/07/27 | Accepted: 2022/10/28 | Published: 2022/11/1
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Ghobadi P, Maleki A, Aali S. Analysis of the Effect of Urban Block Morphology on Wind Flow. GeoRes 2022; 37 (4) :509-516
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1- Department of Architecture and Urban Planning, Faculty of Architecture and Urban Planning, Islamic Art University of Tabriz, Tabriz, Iran
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Introduction
Throughout history, humans have continuously altered their climatic environment through urbanization. A city contains an infinite number of microclimates that are closely connected to its physical structures. This urban–atmospheric system is inherently interdependent, and climate cannot be addressed independently from the city itself. Understanding the microclimates generated by urban blocks can assist in planning and designing new urban areas or redeveloping older ones [Aali et al., 2017]. Proper design of urban blocks can facilitate wind flow and natural ventilation within urban corridors, thereby preventing urban issues such as pollutant trapping, intensified air pollution, and the formation of heat islands, phenomena increasingly observed due to poor design practices. Over the past 40 years, energy demand from buildings (including residential and commercial) has grown by 1.8% annually, and it is projected to rise from 2,790 million tons of oil in 2010 to more than 4,400 million tons by 2050. Most of this growth will occur in developing countries [Van de Graaf, 2014], where a proper understanding of the relationship between urban morphology and wind behavior can help reduce energy demand and prevent resource overuse.
While several climate-related factors, such as age, metabolic rate, and clothing cannot be altered through urban design and physical planning, elements such as airflow circulation and wind behavior can be influenced through urban design tools. These tools can guide the system toward optimal performance. Therefore, addressing urban climatic challenges and responding effectively to climate change impacts requires designing climate-responsive urban spaces. However, morphological factors of urban form which have a significant influence on wind movement and consequently on urban thermal comfortremain largely overlooked [Hesami, 2018]. Studying outdoor wind behavior is essential and serves as a prerequisite in high-density cities [Yao et al., 2017].
Numerous studies have explored aspects of this subject. Among international research, Peng et al. [Peng et al., 2019] have assessed wind using numerical simulation at the urban scale. Their study examined the quantitative correlation between two urban morphological parameters, Floor Area Ratio (FAR) and Building Site Coverage (BSc) and six urban ventilation indices. The findings indicated that local ventilation performance can be effectively improved through logical building arrangements. Feng et al. [Feng et al., 2021] have investigated the relationship between pedestrian-level wind speed ratio and parameters such as block density, floor area ratio, building height, enclosure degree, aspect ratio, and sky view factor (SVF) in a cold-region context, offering insights applicable to the revitalization of traditional blocks in countries with similar latitudes. Additionally, Edussuriya et al. [Edussuriya et al., 2011] have employed 21 indicators to analyze the relationship between air pollutant emissions and urban morphology across 20 districts of Hong Kong.
In Iran, Babaei and Changelavayi have examined urban wind energy potential by analyzing morphological configurations (traditional, gridiron, and high-rise dispersed forms) in Isfahan. Using numerical simulations of wind speed and direction, they found significant correlations between morphological indices and potential wind-flow indicators. These indices enable precise comparison of wind-energy flow outputs across different urban fabrics from an energy-efficient perspective. Their study also identified key physical-morphological parameters affecting wind behavior at neighborhood and city scales [Babaei & Changelavayi, 2020].
In this context, the findings of Bayat and Bemanian can be noted, who proposed building design strategies—such as maintaining appropriate height-to-spacing ratios, orienting buildings toward prevailing winds and ventilation paths, incorporating pilotis, and using cooling towers such as atria and windcatchers. They have also offered strategies related to exhaust management through higher exhaust outlets and landscape design solutions such as orienting tree placement with airflow, using permeable walls allowing wind passage, humid wind flows, and employing porous materials like permeable concrete, all of which enhance wind flow and natural ventilation [Bayat & Bemanian, 2021]. Nonetheless, research on the effects of morphological components on wind behavior remains limited. Saadatjoo and Saligheh found that uniaxial displacement of blocks can have positive or negative effects on outdoor wind patterns, whereas combined displacement leads to airflow obstruction and reduced wind speed. Both uniaxial and combined displacements resulted in higher daylight access compared to the baseline condition [Saadatjoo & Saligheh, 2021].
As evidenced by previous studies, the relationship between urban morphology and wind-speed variations or airflow behavior within urban corridors has not been extensively examined. This research aims to address this gap. The objective of the present study is to understand the influence of four morphological factors associated with urban blocks including enclosure, block volume, building density, and sky view factor [Javanroodi et al., 2022; Maleki et al., 2021; Banerjee et al., 2022] on wind speed and airflow patterns within urban corridors.
Methodology
Selection of Simulation Software
Studies related to wind and airflow patterns in various spaces are typically conducted using either physical or computational models. Computational models are more widely used due to their higher accuracy relative to their lower cost [Robinson, 2012]. In this study, due to the unavailability of a wind tunnel, the analysis was carried out using computational models and CFD-based simulation software. First, commonly used software programs and their features were collected and reviewed based on previous research findings.
Since the present study focuses on microclimatic considerations within urban form performance, the review revealed that ENVI-met offers a broader set of parameters required for evaluating urban microclimates—such as humidity, wind flow, outdoor temperature, and other climatic factors [Aali et al., 2017]. Moreover, ENVI-met provides higher numerical accuracy and more detailed documentation because it is specifically designed for urban studies. Based on a structured comparison, it was identified as the most suitable tool for achieving the objectives of this study. Accordingly, ENVI-met was selected as the computational model for evaluating urban form based on microclimatic parameters.
The software inputs were classified into two categories:
To control interfering parameters and ensure more precise analysis, a single residential block arrangement was examined at 15 different building heights to assess their impact on wind speed. The simulation model represents a hypothetical area measuring 198 × 198 meters. For improved accuracy, at least 18 meters were added to each outer side of the final row of blocks. Each floor height was set to 3 meters. The incoming wind direction was modeled in two scenarios: parallel and diagonal (0° and 45°).
The 0° angle was selected because parallel wind flow at this angle behaves similarly to that at 90°, 180°, and 270°, where the wind strikes the building façades perpendicularly and flows parallel through the corridors between blocks. Therefore, these angles were excluded due to their equivalent conditions. The 45° angle represents an oblique wind approach.
In all models, the block length was set at 42 meters, block width at 12 meters, and street width at 18 meters. The analysis height was fixed at 1.8 meters to reflect pedestrian-level conditions. Complete information related to block specifications used in the modeling process is provided in the study.
Methodology
Selection of Simulation Software
Studies related to wind and airflow patterns in various spaces are typically conducted using either physical or computational models. Computational models are more widely used due to their higher accuracy relative to their lower cost [Robinson, 2012]. In this study, due to the unavailability of a wind tunnel, the analysis was carried out using computational models and CFD-based simulation software. First, commonly used software programs and their features were collected and reviewed based on previous research findings.
Since the present study focuses on microclimatic considerations within urban form performance, the review revealed that ENVI-met offers a broader set of parameters required for evaluating urban microclimates, such as humidity, wind flow, outdoor temperature, and other climatic factors [Aali et al., 2017]. Moreover, ENVI-met provides higher numerical accuracy and more detailed documentation because it is specifically designed for urban studies. Based on a structured comparison, it was identified as the most suitable tool for achieving the objectives of this study. Accordingly, ENVI-met was selected as the computational model for evaluating urban form based on microclimatic parameters.
The software inputs were classified into two categories:
To control interfering parameters and ensure more precise analysis, a single residential block arrangement was examined at 15 different building heights to assess their impact on wind speed. The simulation model represents a hypothetical area measuring 198×198 meters. For improved accuracy, at least 18 meters were added to each outer side of the final row of blocks. Each floor height was set to 3 meters. The incoming wind direction was modeled in two scenarios: parallel and diagonal (0° and 45°).
The 0° angle was selected because parallel wind flow at this angle behaves similarly to that at 90°, 180°, and 270°, where the wind strikes the building façades perpendicularly and flows parallel through the corridors between blocks. Therefore, these angles were excluded due to their equivalent conditions. The 45° angle represents an oblique wind approach.
In all models, the block length was set at 42 meters, block width at 12 meters, and street width at 18 meters. The analysis height was fixed at 1.8 meters to reflect pedestrian-level conditions. Complete information related to block specifications used in the modeling process is provided in the study.
Findings
In this study, by holding all other components constant and focusing on four key morphological factors of urban blocks, wind speed and its variations were analyzed. The simulation outputs indicated that when the wind direction was parallel to the corridor alignment, airflow passed freely through these corridors, sometimes even accelerating beyond the input wind speed due to channeling effects. In contrast, in perpendicular corridors, wind flow decreased substantially, often approaching zero, creating sheltered zones behind buildings where no meaningful airflow occurred.
Under the oblique wind scenario, the airflow split upon striking the corner of a block and continued along the building façades. This deflection increased wind speed toward the leeward ends of the blocks. The main airflow occurred along the northern and eastern façades, while surfaces not directly exposed to wind experienced significantly lower wind speeds.
The dataset associated with morphological factors and mean wind speed showed that as building height increases, mean wind speed and consequently the formation of wind tunnels in corridors also increases under parallel wind conditions. Depending on the season, this can lead to improved thermal comfort in hot climates during summer but reduced comfort in cold climates during winter. A similar pattern was observed for the oblique wind scenario, with an overall increase in mean wind speed across the modeled area.
The simulations demonstrated that three morphological factors including enclosure, built volume, and building density each of which increases with building height and number of floors, were positively associated with increased wind speed. In contrast, the sky view factor exhibited an inverse relationship with mean wind speed.
Comparing the two wind directions, the minimum and maximum mean wind speeds under oblique flow were approximately 1.95 m/s and 3.01 m/s, respectively, while under parallel flow they ranged from 2.55 m/s to 4.13 m/s. These results demonstrate that when buildings are aligned parallel to the prevailing wind direction, mean wind speed increases by roughly 1.5 m/s compared to when buildings are positioned at an angle to the wind. This reflects the greater aerodynamic efficiency of parallel block arrangements in channeling airflow and influencing wind-tunnel effects.
Correlation analysis further showed that, except for the sky view factor, all other parameters demonstrated strong and statistically significant relationships with wind speed when the significance level was below 0.005. Consistent with the graphical results, block height, enclosure, built volume, and density exhibited linear relationships with mean wind speed.
Discussion
The present study was conducted to examine how four morphology-related factors of urban blocks including enclosure, built volume, building density, and sky view factor affect wind speed within urban corridors. Although previous research has addressed wind behavior and urban morphology, most studies have focused either on the scale of individual buildings or on the immediate surroundings of high-rise structures, or they were carried out in cities of other countries using methods other than urban microclimate simulation software. A number of such studies include work by Juan et al. (2021), Wang et al. (2018), Wang et al. (2022), and Ku and Tsai (2020), as well as the studies referenced in the introduction.
For example, Baghaei Daemi et al. (2019) have conducted research aimed at optimizing the form of high-rise buildings and exploring aerodynamic techniques to reduce drag, using Autodesk Flow Design 2014. Rezaiee Hariri et al. (2016) have investigated the impact of high-rise building cross-sections on wind behavior around structures using Gambit and Fluent software. Javanroodi and Nik (2020) have examined interactions between urban morphology indices and extreme weather parameters. Li et al. (2019) have studied both wind fields and urban morphology, applying computational fluid dynamics modeling combined with detailed geospatial building data to simulate urban wind flow. Thus, there was a noticeable gap in research employing ENVI-met simulations at the urban microclimate scale, while keeping selected parameters constant to control conditions, to specifically analyze the role of morphology at defined block orientations. The present study was designed to address this gap.
Findings from previous studies have shown, for instance, that triangular building forms modified aerodynamically with chamfered or conical shapes can minimize drag and offer superior aerodynamic performance for structures around 150 meters tall. Other research indicates that urban morphological parameters such as layout geometry, final height, and urban density can change average wind speed magnitude by up to 23% and air temperature by up to 16% at the microscale. In the present study, however, by holding other parameters constant, it was observed that increasing building height led to higher mean wind speeds under both 0° and 45° wind directions. This may be attributed to increased wind concentration within the spaces between buildings. Furthermore, when blocks were arranged parallel to the wind direction, mean wind speed increased by approximately 1.5 m/s compared to the 45° orientation, representing roughly a 20–30% rise. Based on the simulations, this difference appears to stem from the surface roughness of the concrete-modeled block façades: when the wind strikes the surfaces obliquely, some of its momentum is dissipated, resulting in lower speeds than in the parallel configuration where façade impact is less direct.
Based on the findings, several recommendations can be made for cities or projects with similar wind conditions:
Conclusion
The simulation analysis demonstrated that increasing block height leads to higher mean wind speeds and consequently to the formation of stronger wind tunnels within corridors under both 0° and 45° wind directions. Mean wind speed in block configurations aligned parallel to the prevailing wind was 20–30% higher than in configurations oriented at an angle to the wind. Moreover, wind speed showed a positive relationship with enclosure, built volume, and building density, and an inverse relationship with the sky view factor.
Acknowledgments: The authors express their sincere gratitude to Professor Michael Bruce for granting access to the analytical team.
Ethical Permission: No ethical issues were reported by the authors.
Competing Interests: This article is derived from a doctoral course taught by Professor Aida Maleki at the Islamic Art University of Tabriz, titled “New Approaches in Examining and Evaluating Urban Physics with an Emphasis on Energy Consumption,” taken by the first author.
Authors’ Contributions: Ghobadi P (First Author), Main Researcher /Introduction Writer/Discussion Writer (33.33%);
Maleki A (Second Author), Methodologist (33.33%); Aali SA (Third Author), Statistical Analyst (33.33%)
Funding: This research received no financial support.
Throughout history, humans have continuously altered their climatic environment through urbanization. A city contains an infinite number of microclimates that are closely connected to its physical structures. This urban–atmospheric system is inherently interdependent, and climate cannot be addressed independently from the city itself. Understanding the microclimates generated by urban blocks can assist in planning and designing new urban areas or redeveloping older ones [Aali et al., 2017]. Proper design of urban blocks can facilitate wind flow and natural ventilation within urban corridors, thereby preventing urban issues such as pollutant trapping, intensified air pollution, and the formation of heat islands, phenomena increasingly observed due to poor design practices. Over the past 40 years, energy demand from buildings (including residential and commercial) has grown by 1.8% annually, and it is projected to rise from 2,790 million tons of oil in 2010 to more than 4,400 million tons by 2050. Most of this growth will occur in developing countries [Van de Graaf, 2014], where a proper understanding of the relationship between urban morphology and wind behavior can help reduce energy demand and prevent resource overuse.
While several climate-related factors, such as age, metabolic rate, and clothing cannot be altered through urban design and physical planning, elements such as airflow circulation and wind behavior can be influenced through urban design tools. These tools can guide the system toward optimal performance. Therefore, addressing urban climatic challenges and responding effectively to climate change impacts requires designing climate-responsive urban spaces. However, morphological factors of urban form which have a significant influence on wind movement and consequently on urban thermal comfortremain largely overlooked [Hesami, 2018]. Studying outdoor wind behavior is essential and serves as a prerequisite in high-density cities [Yao et al., 2017].
Numerous studies have explored aspects of this subject. Among international research, Peng et al. [Peng et al., 2019] have assessed wind using numerical simulation at the urban scale. Their study examined the quantitative correlation between two urban morphological parameters, Floor Area Ratio (FAR) and Building Site Coverage (BSc) and six urban ventilation indices. The findings indicated that local ventilation performance can be effectively improved through logical building arrangements. Feng et al. [Feng et al., 2021] have investigated the relationship between pedestrian-level wind speed ratio and parameters such as block density, floor area ratio, building height, enclosure degree, aspect ratio, and sky view factor (SVF) in a cold-region context, offering insights applicable to the revitalization of traditional blocks in countries with similar latitudes. Additionally, Edussuriya et al. [Edussuriya et al., 2011] have employed 21 indicators to analyze the relationship between air pollutant emissions and urban morphology across 20 districts of Hong Kong.
In Iran, Babaei and Changelavayi have examined urban wind energy potential by analyzing morphological configurations (traditional, gridiron, and high-rise dispersed forms) in Isfahan. Using numerical simulations of wind speed and direction, they found significant correlations between morphological indices and potential wind-flow indicators. These indices enable precise comparison of wind-energy flow outputs across different urban fabrics from an energy-efficient perspective. Their study also identified key physical-morphological parameters affecting wind behavior at neighborhood and city scales [Babaei & Changelavayi, 2020].
In this context, the findings of Bayat and Bemanian can be noted, who proposed building design strategies—such as maintaining appropriate height-to-spacing ratios, orienting buildings toward prevailing winds and ventilation paths, incorporating pilotis, and using cooling towers such as atria and windcatchers. They have also offered strategies related to exhaust management through higher exhaust outlets and landscape design solutions such as orienting tree placement with airflow, using permeable walls allowing wind passage, humid wind flows, and employing porous materials like permeable concrete, all of which enhance wind flow and natural ventilation [Bayat & Bemanian, 2021]. Nonetheless, research on the effects of morphological components on wind behavior remains limited. Saadatjoo and Saligheh found that uniaxial displacement of blocks can have positive or negative effects on outdoor wind patterns, whereas combined displacement leads to airflow obstruction and reduced wind speed. Both uniaxial and combined displacements resulted in higher daylight access compared to the baseline condition [Saadatjoo & Saligheh, 2021].
As evidenced by previous studies, the relationship between urban morphology and wind-speed variations or airflow behavior within urban corridors has not been extensively examined. This research aims to address this gap. The objective of the present study is to understand the influence of four morphological factors associated with urban blocks including enclosure, block volume, building density, and sky view factor [Javanroodi et al., 2022; Maleki et al., 2021; Banerjee et al., 2022] on wind speed and airflow patterns within urban corridors.
Methodology
Selection of Simulation Software
Studies related to wind and airflow patterns in various spaces are typically conducted using either physical or computational models. Computational models are more widely used due to their higher accuracy relative to their lower cost [Robinson, 2012]. In this study, due to the unavailability of a wind tunnel, the analysis was carried out using computational models and CFD-based simulation software. First, commonly used software programs and their features were collected and reviewed based on previous research findings.
Since the present study focuses on microclimatic considerations within urban form performance, the review revealed that ENVI-met offers a broader set of parameters required for evaluating urban microclimates—such as humidity, wind flow, outdoor temperature, and other climatic factors [Aali et al., 2017]. Moreover, ENVI-met provides higher numerical accuracy and more detailed documentation because it is specifically designed for urban studies. Based on a structured comparison, it was identified as the most suitable tool for achieving the objectives of this study. Accordingly, ENVI-met was selected as the computational model for evaluating urban form based on microclimatic parameters.
The software inputs were classified into two categories:
- Climatic information, including temperature, wind direction and speed, humidity, and surface roughness, all of which influence wind flow.
- The physical configuration, including site dimensions, buildings, and materials. All buildings were modeled using concrete as the standard material to maintain consistency across all simulations and allow for clearer interpretation of wind behavior.
To control interfering parameters and ensure more precise analysis, a single residential block arrangement was examined at 15 different building heights to assess their impact on wind speed. The simulation model represents a hypothetical area measuring 198 × 198 meters. For improved accuracy, at least 18 meters were added to each outer side of the final row of blocks. Each floor height was set to 3 meters. The incoming wind direction was modeled in two scenarios: parallel and diagonal (0° and 45°).
The 0° angle was selected because parallel wind flow at this angle behaves similarly to that at 90°, 180°, and 270°, where the wind strikes the building façades perpendicularly and flows parallel through the corridors between blocks. Therefore, these angles were excluded due to their equivalent conditions. The 45° angle represents an oblique wind approach.
In all models, the block length was set at 42 meters, block width at 12 meters, and street width at 18 meters. The analysis height was fixed at 1.8 meters to reflect pedestrian-level conditions. Complete information related to block specifications used in the modeling process is provided in the study.
Methodology
Selection of Simulation Software
Studies related to wind and airflow patterns in various spaces are typically conducted using either physical or computational models. Computational models are more widely used due to their higher accuracy relative to their lower cost [Robinson, 2012]. In this study, due to the unavailability of a wind tunnel, the analysis was carried out using computational models and CFD-based simulation software. First, commonly used software programs and their features were collected and reviewed based on previous research findings.
Since the present study focuses on microclimatic considerations within urban form performance, the review revealed that ENVI-met offers a broader set of parameters required for evaluating urban microclimates, such as humidity, wind flow, outdoor temperature, and other climatic factors [Aali et al., 2017]. Moreover, ENVI-met provides higher numerical accuracy and more detailed documentation because it is specifically designed for urban studies. Based on a structured comparison, it was identified as the most suitable tool for achieving the objectives of this study. Accordingly, ENVI-met was selected as the computational model for evaluating urban form based on microclimatic parameters.
The software inputs were classified into two categories:
- Climatic information, including temperature, wind direction and speed, humidity, and surface roughness, all of which influence wind flow.
- The physical configuration, including site dimensions, buildings, and materials. All buildings were modeled using concrete as the standard material to maintain consistency across all simulations and allow for clearer interpretation of wind behavior.
To control interfering parameters and ensure more precise analysis, a single residential block arrangement was examined at 15 different building heights to assess their impact on wind speed. The simulation model represents a hypothetical area measuring 198×198 meters. For improved accuracy, at least 18 meters were added to each outer side of the final row of blocks. Each floor height was set to 3 meters. The incoming wind direction was modeled in two scenarios: parallel and diagonal (0° and 45°).
The 0° angle was selected because parallel wind flow at this angle behaves similarly to that at 90°, 180°, and 270°, where the wind strikes the building façades perpendicularly and flows parallel through the corridors between blocks. Therefore, these angles were excluded due to their equivalent conditions. The 45° angle represents an oblique wind approach.
In all models, the block length was set at 42 meters, block width at 12 meters, and street width at 18 meters. The analysis height was fixed at 1.8 meters to reflect pedestrian-level conditions. Complete information related to block specifications used in the modeling process is provided in the study.
Findings
In this study, by holding all other components constant and focusing on four key morphological factors of urban blocks, wind speed and its variations were analyzed. The simulation outputs indicated that when the wind direction was parallel to the corridor alignment, airflow passed freely through these corridors, sometimes even accelerating beyond the input wind speed due to channeling effects. In contrast, in perpendicular corridors, wind flow decreased substantially, often approaching zero, creating sheltered zones behind buildings where no meaningful airflow occurred.
Under the oblique wind scenario, the airflow split upon striking the corner of a block and continued along the building façades. This deflection increased wind speed toward the leeward ends of the blocks. The main airflow occurred along the northern and eastern façades, while surfaces not directly exposed to wind experienced significantly lower wind speeds.
The dataset associated with morphological factors and mean wind speed showed that as building height increases, mean wind speed and consequently the formation of wind tunnels in corridors also increases under parallel wind conditions. Depending on the season, this can lead to improved thermal comfort in hot climates during summer but reduced comfort in cold climates during winter. A similar pattern was observed for the oblique wind scenario, with an overall increase in mean wind speed across the modeled area.
The simulations demonstrated that three morphological factors including enclosure, built volume, and building density each of which increases with building height and number of floors, were positively associated with increased wind speed. In contrast, the sky view factor exhibited an inverse relationship with mean wind speed.
Comparing the two wind directions, the minimum and maximum mean wind speeds under oblique flow were approximately 1.95 m/s and 3.01 m/s, respectively, while under parallel flow they ranged from 2.55 m/s to 4.13 m/s. These results demonstrate that when buildings are aligned parallel to the prevailing wind direction, mean wind speed increases by roughly 1.5 m/s compared to when buildings are positioned at an angle to the wind. This reflects the greater aerodynamic efficiency of parallel block arrangements in channeling airflow and influencing wind-tunnel effects.
Correlation analysis further showed that, except for the sky view factor, all other parameters demonstrated strong and statistically significant relationships with wind speed when the significance level was below 0.005. Consistent with the graphical results, block height, enclosure, built volume, and density exhibited linear relationships with mean wind speed.
Discussion
The present study was conducted to examine how four morphology-related factors of urban blocks including enclosure, built volume, building density, and sky view factor affect wind speed within urban corridors. Although previous research has addressed wind behavior and urban morphology, most studies have focused either on the scale of individual buildings or on the immediate surroundings of high-rise structures, or they were carried out in cities of other countries using methods other than urban microclimate simulation software. A number of such studies include work by Juan et al. (2021), Wang et al. (2018), Wang et al. (2022), and Ku and Tsai (2020), as well as the studies referenced in the introduction.
For example, Baghaei Daemi et al. (2019) have conducted research aimed at optimizing the form of high-rise buildings and exploring aerodynamic techniques to reduce drag, using Autodesk Flow Design 2014. Rezaiee Hariri et al. (2016) have investigated the impact of high-rise building cross-sections on wind behavior around structures using Gambit and Fluent software. Javanroodi and Nik (2020) have examined interactions between urban morphology indices and extreme weather parameters. Li et al. (2019) have studied both wind fields and urban morphology, applying computational fluid dynamics modeling combined with detailed geospatial building data to simulate urban wind flow. Thus, there was a noticeable gap in research employing ENVI-met simulations at the urban microclimate scale, while keeping selected parameters constant to control conditions, to specifically analyze the role of morphology at defined block orientations. The present study was designed to address this gap.
Findings from previous studies have shown, for instance, that triangular building forms modified aerodynamically with chamfered or conical shapes can minimize drag and offer superior aerodynamic performance for structures around 150 meters tall. Other research indicates that urban morphological parameters such as layout geometry, final height, and urban density can change average wind speed magnitude by up to 23% and air temperature by up to 16% at the microscale. In the present study, however, by holding other parameters constant, it was observed that increasing building height led to higher mean wind speeds under both 0° and 45° wind directions. This may be attributed to increased wind concentration within the spaces between buildings. Furthermore, when blocks were arranged parallel to the wind direction, mean wind speed increased by approximately 1.5 m/s compared to the 45° orientation, representing roughly a 20–30% rise. Based on the simulations, this difference appears to stem from the surface roughness of the concrete-modeled block façades: when the wind strikes the surfaces obliquely, some of its momentum is dissipated, resulting in lower speeds than in the parallel configuration where façade impact is less direct.
Based on the findings, several recommendations can be made for cities or projects with similar wind conditions:
- reducing wind speed through lower building heights and enhanced sky view factor in cold climates;
- increasing wind speed through higher building elevations and reduced sky view factor in hot climates;
- implementing wind-enhancement strategies where increased ventilation is required in certain urban spaces;
- employing urban design measures to modulate wind speed in corridors depending on incoming wind conditions and thermal comfort requirements; and
- increasing wind speed, reducing sky view factor, and increasing block height, enclosure, or building density to mitigate urban heat island effects and aid pollutant dispersion.
- lack of access to the full version of the software, resulting in lower simulation accuracy due to constraints on the selectable domain size;
- lack of access to multi-core simulation and correspondingly long computation times;
- restrictions on simulation duration due to the slower performance of the free version;
- inability to utilize a wind tunnel laboratory, making the study fully dependent on computer simulation; and
- the need to keep most parameters constant for simulation purposes, which differs from real urban conditions where multiple factors operate simultaneously and cannot be held fixed.
Conclusion
The simulation analysis demonstrated that increasing block height leads to higher mean wind speeds and consequently to the formation of stronger wind tunnels within corridors under both 0° and 45° wind directions. Mean wind speed in block configurations aligned parallel to the prevailing wind was 20–30% higher than in configurations oriented at an angle to the wind. Moreover, wind speed showed a positive relationship with enclosure, built volume, and building density, and an inverse relationship with the sky view factor.
Acknowledgments: The authors express their sincere gratitude to Professor Michael Bruce for granting access to the analytical team.
Ethical Permission: No ethical issues were reported by the authors.
Competing Interests: This article is derived from a doctoral course taught by Professor Aida Maleki at the Islamic Art University of Tabriz, titled “New Approaches in Examining and Evaluating Urban Physics with an Emphasis on Energy Consumption,” taken by the first author.
Authors’ Contributions: Ghobadi P (First Author), Main Researcher /Introduction Writer/Discussion Writer (33.33%);
Maleki A (Second Author), Methodologist (33.33%); Aali SA (Third Author), Statistical Analyst (33.33%)
Funding: This research received no financial support.
Keywords:
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