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Impacts of upstream buildings on the flow fields and pollutant distributions in street canyons |
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Abstract Numerical simulations were conducted to study the flow and concentration fields in both regular and staggered street canyons with different layouts of the upstream buildings. The results showed that the upstream buildings changed the wind speed and distorted the secondary flows in the canyons thus had significant effects on the flow and concentration fields. In the regular street canyons, the average pollutant concentrations could be reduced regardless of layout of the upstream buildings. The average concentration would be overestimated by numerical simulations without considering the existence of the upstream buildings in practice. In the staggered street canyons, when upstream buildings are aligned with street canyons, the pollutant concentrations in the street canyon could be reduced by the blocking effect. In contrast, when the upstream buildings are staggered with the canyons, the concentrations could be increased. The results also showed that the pollutant dispersion and removal in street canyons are effected by both the airflow velocity and local vortex characteristics.
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Received: 02 April 2014
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