Application and numerical error analysis of multiscale method for air flow, heat and pollutant transfer through different scale urban areas

2019 ◽  
Vol 149 ◽  
pp. 349-365 ◽  
Author(s):  
Peng-Yi Cui ◽  
Yan Zhang ◽  
Jin-Hao Zhang ◽  
Yuan-Dong Huang ◽  
Wen-Quan Tao
Author(s):  
Elahe Mirabi ◽  
Nasrollahi Nazanin

<p>Designing urban facades is considered as a major factor influencing issues<br />such as natural ventilation of buildings and urban areas, radiations in the<br />urban canyon for designing low-energy buildings, cooling demand for<br />buildings in urban area, and thermal comfort in urban streets. However, so<br />far, most studies on urban topics have been focused on flat facades<br />without details of urban layouts. Hence, the effect of urban facades with<br />details such as the balcony and corbelling on thermal comfort conditions<br />and air flow behavior are discussed in this literature review. <strong>Aim</strong>: This<br />study was carried out to investigate the effective factors of urban facades,<br />including the effects of building configuration, geometry and urban<br />canyon’s orientation. <strong>Methodology and Results</strong>: According to the results,<br />the air flow behavior is affected by a wide range of factors such as wind<br />conditions, urban geometry and wind direction. Urban façade geometry<br />can change outdoor air flow pattern, thermal comfort and solar access.<br /><strong>Conclusion, significance and impact study</strong>: In particular, the geometry of<br />the facade, such as indentation and protrusion, has a significant effect on<br />the air flow and thermal behavior in urban facades and can enhance<br />outdoor comfort conditions. Also, Alternation in façade geometry can<br />affect pedestrians' comfort and buildings energy demands.</p>


2011 ◽  
Vol 26 (1-3) ◽  
pp. 215-225 ◽  
Author(s):  
Zdenêk Palatý ◽  
Helena Bendová

Author(s):  
Debasmita Lohar ◽  
Milos Prokop ◽  
Eva Darulova

Author(s):  
W. K. Chow

Consequent to a big gas station fire in Macau and another recent one affected by a nearby explosion in a fireworks factory in China, there are concerns on the fire safety issues of gas stations in urban areas. Those two incidents were not too terrible but the situation would be much worse if there was strong wind, especially in a dense urban area where buildings are closely built together. There are many gas stations built within residential areas in Hong Kong. Wind-induced air movement is a transient phenomenon which depends not only on the wind speeds measured at some designated sites, but is also strongly affected by the surrounding environment. For a gas station located adjacent to a taller building, turbulent effects due to incident wind fields would be important. This is not just a safety problem of the gas station, nor for any single building. A risk management system should be worked out by the Authority in the estate district, suburb, or even the whole city. The problem must be considered carefully for cities with dense population and numerous highrise buildings. Computational fluid dynamics (CFD) is a suitable tool for hazard assessment on the spreading of smoke and heat. In this paper, the wind-induced air flow in a gas station fire next to a building was studied by CFD. The CFD simulator selected is the Fire Dynamics Simulator (FDS) version 3.01. Acoustic filtering technique was applied to remove the flow with high Mach number and large-eddy simulations (LES) were applied to model smaller turbulent scales. Different scenarios on the gas station position, building height and distance away from a vertical wall of the building were simulated. Wind effect was simulated by taking the incident air flow as a parabolic boundary layer. The results are very useful for working out risk management in case of accidents. Note that smoke or even flame will spread by following the wind-induced air motion.


2000 ◽  
Vol 162 (3-4) ◽  
pp. 269-298 ◽  
Author(s):  
Stéphane Scaillet

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