Effects of plume buoyancy and momentum on the near-wake flow structure and dispersion behind an idealized building

Héctor A. Olvera, Ahsan R. Choudhuri, Wen Whai Li

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Dispersion simulations of buoyant and neutral plume releases within the recirculation cavity behind a cubical building were performed using a commercially available CFD code and the RNG k-ε turbulence model. Plume buoyancy was observed to affect the size and shape of the cavity region and the flow structure and concentration profiles within. Source momentum of a neutral plume release had similar effects on the flow structure and the cavity region to that caused by plume buoyancy. However, the effects of momentum on the concentration profiles were noticeably different from that caused by plume buoyancy. Plumes released immediately downwind of a cubical building appear to alter the flow field and dispersion characteristics of the cavity recirculation region due to their inherent momentum and buoyancy. A greater fraction of a plume was captured inside the wake as the plume became increasingly buoyant. Contrarily, greater plume momentum resulted in smaller plume fractions captured inside the wake. Inclusion of these effects in the downwash algorithms would improve the accuracy of modeling results for far-field concentration distributions and would be mandatory in accident assessments where accurate predictions of short-term, near-field concentration fluctuations near source releases are required.

Original languageEnglish (US)
Pages (from-to)209-228
Number of pages20
JournalJournal of Wind Engineering and Industrial Aerodynamics
Issue number2
StatePublished - Feb 2008
Externally publishedYes


  • Atmospheric dispersion
  • Building wake
  • CFD
  • Numerical simulation
  • RNG k-ε turbulence model

ASJC Scopus subject areas

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


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