Analysis of fluctuating characteristics of wind-induced airflow through a single opening using LES modeling and the tracer gas technique

Zhengtao Ai, C. M. Mak

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The turbulent nature of wind significantly complicates the airflow-exchange process at single openings that function as both inlets and outlets simultaneously. For such flow problems, describing the ventilation rate using a constant value is insufficient if the fluctuating intensity is too large. This paper uses a large eddy simulation (LES) model combined with the tracer gas concentration decay method to investigate fluctuating ventilation characteristics through a single opening under various approaching wind directions. The numerical method is validated against a field measurement of single-sided ventilation rates. Results show that wind direction (which characterizes the external airflow pattern) greatly influences the airflow exchange at a single opening. The ventilation rate is relatively steady for a windward opening and shows more unsteadiness for a lateral and a leeward opening. The airflow-exchange process is mainly driven by the mean flow at the windward opening and is dominated by the turbulent flow at the lateral opening. The findings from this study imply that the turbulence-induced component of single-sided ventilation rates should always be considered, especially for non-windward openings. (C) 2014 Elsevier Ltd. All rights reserved.
Original languageEnglish
JournalBuilding and Environment
Volume80
Pages (from-to)249-258
Number of pages10
ISSN0360-1323
DOIs
Publication statusPublished - 2014
Externally publishedYes

Keywords

  • Fluctuating ventilation rate
  • LES model
  • Single-sided ventilation
  • Tracer gas technique
  • Wind direction

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