Paper 3
Domain Decomposition Technique
Applied to the Evaluation of Cross-Ventilation Performance of Opening
Positions of a Building
Takashi
Kurabuchi1, Masaaki Ohba2 and Toshihiro Nonaka3
1Tokyo University of Science, Tokyo, Japan
2Tokyo Polytechnic University, Kanagawa, Japan
3TOSTEM Corporation, Tokyo, Japan
Abstract
The prediction of indoor airflow is indispensable in evaluating the
thermal sensation of occupants in a cross-ventilated space because
enhanced heat loss due to the elevated convective heat transfer in the
occupied zone is an essential part of improving thermal comfort. A domain
decomposition technique was developed to separate CFD for internal
cross-ventilation flow from external flow outside buildings, and to
predict indoor airflow with reasonable computational effort and sufficient
accuracy. Decoupling of the flow fields inside and outside the building
not only improves efficiency of CFD but also enables optimization of
opening positions without taking the external flow field into account.
Indoor airflow fields of a cross-ventilated building calculated with CFD
using the domain decomposition technique were in good agreement with CFD
results for full flow field simulation and measurements by wind tunnel
experiment. Case studies were conducted to evaluate cross-ventilation
performance of a variety of opening positions under the meteorological
conditions of Tokyo and Osaka, and it was found that the relative air
velocity in the occupied zone to the air velocity passing through the
opening was mainly due to the opening positions.
Key words: cross-ventilation, discharge coefficient, CFD, wind
tunnel experiment.
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