Large-eddy simulation of turbulent flow and dispersion over a complex urban street canyon

Kiyoung Moon, Jeong Min Hwang, Byung Gu Kim, Changhoon Lee, Jung il Choi

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Turbulent flow and dispersion characteristics over a complex urban street canyon are investigated by large-eddy simulation using a modified version of the Fire Dynamics Simulator. Two kinds of subgrid scale (SGS) models, the constant coefficient Smagorinsky model and the Vreman model, are assessed. Turbulent statistics, particularly turbulent stresses and wake patterns, are compared between the two SGS models for three different wind directions. We found that while the role of the SGS model is small on average, the local or instantaneous contribution to total stress near the surface or edge of the buildings is not negligible. By yielding a smaller eddy viscosity near solid surfaces, the Vreman model appears to be more appropriate for the simulation of a flow in a complex urban street canyon. Depending on wind direction, wind fields, turbulence statistics, and dispersion patterns show very different characteristics. Particularly, tall buildings near the street canyon predominantly generate turbulence, leading to homogenization of the mean flow inside the street canyon. Furthermore, the release position of pollutants sensitively determines subsequent dispersion characteristics.

Original languageEnglish
Pages (from-to)1381-1403
Number of pages23
JournalEnvironmental Fluid Mechanics
Volume14
Issue number6
DOIs
Publication statusPublished - 2014 Dec 1

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Water Science and Technology

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