Using CFD to investigate ventilation characteristics of vaults as wind-inducing devices in buildings

Abstract

This paper investigates the potential of the vaulted roofs for improving wind-induced natural ventilation, using computational fluid dynamics (CFD) three-dimensional modelling. This has been carried out in a parametric study considering different climatic and geometrical parameters. Using Fluent 5.5 program, natural ventilation performance has been modelled and assessed according to the value of airflow rate, and the quality of internal airflow distribution. It has been concluded that utilisation of vaulted roofs for natural ventilation increases inflow rate of the building, and re-distribute internal airflow currents by attracting some of the air to leave through roof openings instead of walls openings. This has improved ventilation conditions in the upstream and central zones of the building, but not in the downstream zone. Natural ventilation performance of two equivalent domed and vaulted roofs has also been compared. Results showed that there are many similarities between domed and vaulted roofs in terms of their natural ventilation performance. The advantage of any roof shape in air suction is highly dependant on wind direction.