Atmosphere (대기)

Korean Meteorological Society (한국기상학회)
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Effects of Building-roof Cooling on Scalar Dispersion in Urban Street Canyons

도시 협곡에서 건물 지붕 냉각이 스칼라 물질 확산에 미치는 영향

  • Park, Soo-Jin (Department of Environmental Atmospheric Sciences, Pukyong National University) ;
  • Kim, Jae-Jin (Department of Environmental Atmospheric Sciences, Pukyong National University)
  • 박수진 (부경대학교 환경대기과학과) ;
  • 김재진 (부경대학교 환경대기과학과)
  • Received : 2014.03.23
  • Accepted : 2014.06.23
  • Published : 2014.09.30
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Abstract

In this study, the effects of building-roof cooling on scalar dispersion in three-dimensional street canyons are investigated using a computational fluid dynamics (CFD) model. For this, surface temperature of building roof is systematically changed and non-reactive pollutants are released from street bottom in urban street canyons with the aspect ratio of 1. The characteristics of flow, air temperature, and non-reactive pollutant dispersion in the control experiment are analyzed first. Then, the effects of building-roof cooling are investigated by comparing the results with those in the control experiment. In the control experiment, a portal vortex which is a secondary flow induced by ambient air flow is formed in each street canyon. Averaged air temperature is higher inside the street canyon than in both sides of the street canyon, because warmer air is coming into the street canyon from the roof level. However, air temperature near the street bottom is lower inside the street canyon due to the inflow of cooler air from both sides of the street canyon. As building-roof temperature decreases, wind speed at the roof level increases and portal vortex becomes intensified (that is, downdraft, reverse flow, and updraft becomes stronger). Building-roof cooling contributes to the reduction of average concentration of the non-reactive pollutants and average air temperature in the street canyon. The results imply that building-roof cooling has positive effects on improvement of thermal environment and air quality in urban areas.

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References

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