Paper 7: Volume 4 No.3 December 2005 Edition
CFD Reliability Issues
in the Prediction of Airflows in a Naturally Ventilated Building
Joseph M.
Horan1 and Donal P. Finn2
1Urban
Institute
Ireland
,
University
College
Dublin
,
Ireland
2School of Electrical, Electronic and Mechanical Engineering,
University
College
Dublin
,
Ireland
Abstract
The potential for prediction error when using computational fluid dynamics
(CFD) for investigating internal building airflows is assessed in the
current paper. The ability of a proprietary CFD code, CFX, to simulate
buoyant and forced airflow regimes, typical of a naturally ventilated
building, are investigated using two experimental case studies from the
literature. Comparisons are then made between simulated and measured
airflows for a naturally ventilated building. Results from the two case
studies indicate that structured meshes are less dependent on mesh density
and yield consistent convergence and accuracy when coupled with the
k-ε or k-ω turbulence models. Comparison of CFD predicted
airflows with the full-scale building airflows was challenging due to
scatter in the measured data. A structured mesh in conjunction with either
the k-ε or k-ω turbulence models, showed reasonable correlation
with the measured airflows, with both models performing equally.
Key words: Natural
ventilation, computational fluid dynamics (CFD), meshing, turbulence
model, full-scale building simulation, full-scale building measurements,
reliability.
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