CFD simulation of the effect of an upstream building on the inter-unit dispersion in a multi-story building in two wind directions

D. J. Cui, Cheuk Ming Mak, K. C.S. Kwok, Z. T. Ai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

36 Citations (Scopus)


Previous studies on inter-unit dispersion are limited to isolated buildings. The influence of an upstream interfering building may significantly modify the indoor airflow characteristics of the wind-induced natural ventilated downstream interfered building. Motivated by the findings in previous studies, namely that infectious respiratory aerosols exhausted from a unit can re-enter into another unit in the same building through building envelope openings, this study investigates the inter-unit pollutant dispersion around a multi-story building in two wind directions by employing the computational fluid dynamics (CFD) method. The CFD model employed in this study has been validated against previous experimental data. The results show that the presence of an upstream building greatly changes the path lines around the downstream target building and the pollutant transportation routes around it. The presence of a low upstream building also greatly increases the average air exchange rate (ACH) values and the pollutant re-entry ratios (Rk) below the source unit on the windward side of the downstream target building for normal wind incidence. However, the presence of a high upstream building greatly increases the average ACH values on the windward side and increases the Rkon the leeward side of the downstream building for oblique wind incidence.
Original languageEnglish
Pages (from-to)31-41
Number of pages11
JournalJournal of Wind Engineering and Industrial Aerodynamics
Publication statusPublished - 1 Mar 2016


  • CFD
  • Inter-unit dispersion
  • Natural ventilation
  • Upstream building
  • Wind directions

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Renewable Energy, Sustainability and the Environment
  • Mechanical Engineering

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