Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating
Author(s)
Koh, Tieh Yong; Norford, Leslie Keith; Liu, Chun-Ho; Entekhabi, Dara; Leung, Dennis Y. C.; Li, Xianxiang; Britter, Rex E; ... Show more Show less
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Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification was produced by heating the ground of the street canyon. Using the Boussinesq approximation, thermal buoyancy forces were taken into account in both the Navier–Stokes equations and the transport equation for subgrid-scale turbulent kinetic energy (TKE). The LESs were validated against experimental data obtained in wind-tunnel studies before the model was applied to study the detailed turbulence, temperature, and pollutant dispersion characteristics in the street canyon of aspect ratio 1. The effects of different Richardson numbers (Ri) were investigated. The ground heating significantly enhanced mean flow, turbulence, and pollutant flux inside the street canyon, but weakened the shear at the roof level. The mean flow was observed to be no longer isolated from the free stream and fresh air could be entrained into the street canyon at the roof-level leeward corner. Weighed against higher temperature, the ground heating facilitated pollutant removal from the street canyon.
Date issued
2010-08Department
Massachusetts Institute of Technology. Department of Architecture; Massachusetts Institute of Technology. Department of Civil and Environmental Engineering; Massachusetts Institute of Technology. Department of Urban Studies and Planning; Singapore-MIT Alliance in Research and Technology (SMART)Journal
Boundary - Layer Meterology
Publisher
Springer-Verlag
Citation
Li, Xian-Xiang et al. “Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating.” Boundary-Layer Meteorology 137.2 (2010): 187–204.
Version: Final published version
ISSN
0006-8314
1573-1472