Effects of building lift-up design on the wind environment for pedestrians

2015 ◽  
Vol 26 (9) ◽  
pp. 1214-1231 ◽  
Author(s):  
Qian Xia ◽  
Xiaoping Liu ◽  
Jianlei Niu ◽  
Kenny C. S. Kwok
Keyword(s):  
Wind Speed ◽  
Pollutant Dispersion ◽  
Building Blocks ◽  
Strong Wind ◽  
Wind Environment ◽  
Thermal Environments ◽  
Low Wind Speed ◽  
Scale Models ◽  
Open Ground ◽  
Air Ventilation

Low airflow or poor outdoor ventilation around building blocks can negatively influence pollutant dispersion in the surroundings and indoor air quality, and increase the risks of airborne transmission of infectious diseases. However, there have been few studies addressing the wind environment, thermal comfort and other concerns at the pedestrian level. Buildings with a lift-up design may have a number of impacts on the pedestrian-level wind and thermal environments. Three building configurations that resulted in the lowest wind speed zones were identified from a previous study. A 3.5 m high open ground floor was added to each of the three configurations, and scale models of the three designs were studied in a wind tunnel to assess their influences on airflow and ventilation around the buildings. Undesirable areas of low wind speed leading to poor air ventilation and, on the other side of extreme, areas of discomfort due to strong wind conditions were both identified, and their practical implications are discussed.

Pollutant dispersion simulation for low wind speed condition by the ILS method

2005 ◽  
Vol 39 (34) ◽  
pp. 6282-6288 ◽  
Author(s):  
Jonas C. Carvalho ◽  
Marco Túllio M.B. de Vilhena
Keyword(s):  
Wind Speed ◽  
Pollutant Dispersion ◽  
Speed Condition ◽  
Low Wind Speed

Impact of wind speeds on turbulent transport of carbon dioxide (CO2) fluxes at a tropical location in Ile - Ife, southwest Nigeria

2020 ◽  
Author(s):  
Theodora Bello ◽  
Adewale Ajao ◽  
Oluwagbemiga Jegede
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Land Surface ◽  
Stable Boundary Layer ◽  
Turbulent Transport ◽  
Strong Wind ◽  
Stable Boundary ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Tropical Area

<p>The study investigates impact of wind speeds on the turbulent transport of CO<sub>2 </sub>fluxes for a land-surface atmosphere interface in a low-wind tropical area between May 28<sup>th</sup> and June 14<sup>th</sup>, 2010; and May 24<sup>th</sup> and June 15<sup>th</sup>, 2015. Eddy covariance technique was used to acquire turbulent mass fluxes of CO<sub>2</sub> and wind speed at the study site located inside the main campus of Obafemi Awolowo University, Ile – Ife, Nigeria. The results showed high levels of CO<sub>2 </sub>fluxes at nighttime attributed to stable boundary layer conditions and low wind speed. Large transport and distribution of CO<sub>2 </sub>fluxes were observed in the early mornings due to strong wind speeds recorded at the study location. In addition, negative CO<sub>2 </sub>fluxes were observed during the daytime attributed to prominent convective and photosynthetic activities. The study concludes there was an inverse relationship between turbulent transport of CO<sub>2 </sub>fluxes and wind speed for daytime period while nighttime CO<sub>2</sub> fluxes showed no significant correlation.</p><p><strong>Keywords</strong>: CO<sub>2 </sub>fluxes, Wind speed, Turbulent transport, Low-wind tropical area, Stable boundary layer</p>

scholarly journals A Review on the Building Wind Impact through On-site Monitoring in Haeundae Marine City: 2021 12th Typhoon OMAIS Case Study

2021 ◽  
Vol 35 (6) ◽  
pp. 414-425
Author(s):  
Jongyeong Kim ◽  
Byeonggug Kang ◽  
Yongju Kwon ◽  
Seungbi Lee ◽  
Soonchul Kwon
Keyword(s):  
Wind Speed ◽  
Weather Conditions ◽  
Speed Ratio ◽  
Wind Effect ◽  
Strong Wind ◽  
Average Wind Speed ◽  
Wind Environment ◽  
High Rise ◽  
Site Monitoring ◽  
Surrounding Areas

Overcrowding of high-rise buildings in urban zones change the airflow pattern in the surrounding areas. This causes building wind, which adversely affects the wind environment. Building wind can generate more serious social damage under extreme weather conditions such as typhoons. In this study, to analyze the wind speed and wind speed ratio quantitatively, we installed five anemometers in Haeundae, where high-rise buildings are dense, and conducted on-site monitoring in the event of typhoon OMAIS to determine the characteristics of wind over skyscraper towers surround the other buildings. At point M-2, where the strongest wind speed was measured, the maximum average wind speed in 1 min was observed to be 28.99 m/s, which was 1.7 times stronger than that at the ocean observatory, of 17.0 m/s, at the same time. Furthermore, when the wind speed at the ocean observatory was 8.2 m/s, a strong wind speed of 24 m/s was blowing at point M-2, and the wind speed ratio compared to that at the ocean observatory was 2.92. It is judged that winds 2–3 times stronger than those at the surrounding areas can be induced under certain conditions due to the building wind effect. To verify the degree of wind speed, we introduced the Beaufort wind scale. The Beaufort numbers of wind speed data for the ocean observatory were mostly distributed from 2 to 6, and the maximum value was 8; however, for the observation point, values from 9 to 11 were observed. Through this study, it was possible to determine the characteristics of the wind environment in the area around high-rise buildings due to the building wind effect.

Simulation on Computational Fluid Dynamics of Flow Field and Pollutant Dispersion in Block of Buildings

2013 ◽  
Vol 327 ◽  
pp. 250-255
Author(s):  
Rong Huang ◽  
Kai Hua Li ◽  
Bo Wang
Keyword(s):  
Fluid Dynamics ◽  
Wind Speed ◽  
Motor Vehicle ◽  
Flow Distribution ◽  
Pollutant Dispersion ◽  
Vehicle Exhaust ◽  
Low Wind Speed ◽  
The Social ◽  
Opposite Situation ◽  
Pollutants Dispersion

With the social development, motor vehicle exhaust has become a major source of pollution in the city today, so it is necessary to research the effect of the wind field around buildings and pollutants dispersion on human health. In this paper, we using Fluid Dynamics method to simulate the pollutants dispersion under different wind direction. The results showed that the maximum wind speed of the buildings in the same horizontal plane appeared in the entrance of the street. When the inflow velocity, wind directions are different, the air flow distribution is different in group of buildings. Pollutants are prone to accumulate in the place of low wind speed, atmospheric instability, and weak turbulence intensity. The concentration of pollutants from lower to upper gradually reduced, but it will appear opposite situation in the vortex.

Development and Validation of a Thermodynamic Model for Predicting Traffic-Related Pollutants Dispersion in Urban Street Canyons under Low Wind Speed Conditions

2012 ◽  
Vol 157-158 ◽  
pp. 710-713
Author(s):  
Guo Hua Gao ◽  
Jing Liu ◽  
Fei Ma ◽  
Wei Dong Luo
Keyword(s):  
Wind Speed ◽  
Thermodynamic Model ◽  
Street Canyon ◽  
Pollutant Dispersion ◽  
Shielding Effect ◽  
Street Canyons ◽  
Urban Street ◽  
Low Wind Speed ◽  
Urban Street Canyons ◽  
Pollutants Dispersion

To study the thermal effects on pollutant dispersion in the street canyon, a thermodynamic model is developed in this paper to predict surface temperature in street canyon environment, which can offer boundary conditions for CFD model. This model considered the shielding effect of buildings on solar radiation, the multi-reflection of radiation between building surfaces and the road. Furthermore, sensible heat exchange between the canyon space and the overlaying atmosphere was also modeled based on the classical theory of dynamics of atmospheric boundary layer. The reliability of this model is validated through a field measurement. Based on the thermodynamic model, a coupled calculation method is presented to predict traffic-related pollutants dispersion in urban street canyons under low wind speed conditions.

Two mechanisms for accelerated diffusion of COVID-19 outbreaks in regions with high intensity of population and polluting industrialization: the air pollution-to-human and human-to-human transmission dynamics (Preprint)

2020 ◽  
Author(s):  
Mario Coccia
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Critical Role ◽  
Meteorological Condition ◽  
Meteorological Conditions ◽  
Lessons Learned ◽  
Transmission Dynamics ◽  
Critical Threshold ◽  
Viral Infectivity ◽  
Low Wind Speed

BACKGROUND Coronavirus disease 2019 (COVID-19) is viral infection that generates a severe acute respiratory syndrome with serious pneumonia that may result in progressive respiratory failure and death. OBJECTIVE This study has two goals. The first is to explain the main factors determining the diffusion of COVID-19 that is generating a high level of deaths. The second is to suggest a strategy to cope with future epidemic threats with of accelerated viral infectivity in society. METHODS Correlation and regression analyses on on data of N=55 Italian province capitals, and data of infected individuals at as of April 2020. RESULTS The main results are: o The accelerate and vast diffusion of COVID-19 in North Italy has a high association with air pollution. o Hinterland cities have average days of exceeding the limits set for PM10 (particulate matter 10 micrometers or less in diameter) equal to 80 days, and an average number of infected more than 2,000 individuals as of April 1st, 2020, coastal cities have days of exceeding the limits set for PM10 equal to 60 days and have about 700 infected in average. o Cities that average number of 125 days exceeding the limits set for PM10, last year, they have an average number of infected individual higher than 3,200 units, whereas cities having less than 100 days (average number of 48 days) exceeding the limits set for PM10, they have an average number of about 900 infected individuals. o The results reveal that accelerated transmission dynamics of COVID-19 in specific environments is due to two mechanisms given by: air pollution-to-human transmission and human-to-human transmission; in particular, the mechanisms of air pollution-to-human transmission play a critical role rather than human-to-human transmission. o The finding here suggests that to minimize future epidemic similar to COVID-19, the max number of days per year in which cities can exceed the limits set for PM10 or for ozone, considering their meteorological condition, is less than 50 days. After this critical threshold, the analytical output here suggests that environmental inconsistencies because of the combination between air pollution and meteorological conditions (with high moisture%, low wind speed and fog) trigger a take-off of viral infectivity (accelerated epidemic diffusion) with damages for health of population, economy and society. CONCLUSIONS Considering the complex interaction between air pollution, meteorological conditions and biological characteristics of viral infectivity, lessons learned for COVID-19 have to be applied for a proactive socioeconomic strategy to cope with future epidemics, especially an environmental policy based on reduction of air pollution mainly in hinterland zones of countries, having low wind speed, high percentage of moisture and fog that create an environment that can damage immune system of people and foster a fast transmission of viral infectivity similar to the COVID-19. CLINICALTRIAL not applicable

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