Computational analysis of wind driven natural ventilation in buildings

Abstract

The design of natural ventilation in buildings is often performed by means of computational fluid dynamics (CFD) techniques, whose application is gaining popularity. In the present study, Reynolds averaged Navier–Stokes equation (RANS) approach is applied to wind driven natural ventilation in a cubic building. Two different models are considered, namely the two-equation k– ɛ model and the Renormalization Group (RNG) theory. The velocity and pressure distribution inside and around the building are determined, as well as the ventilation rate, for three different configurations: cross ventilation, single-sided ventilation with an opening on the windward wall and single-sided ventilation with an opening on the leeward wall. The numerical results are compared with experimental data, showing a good agreement, particularly when using RNG. The discrepancy in the determination of the ventilation rate is reasonable and the flow distribution inside the building is properly described when RNG model is used. However, the k– ɛ model fails to determine the correct velocity components near the horizontal surfaces. According to these results, the RNG model can be considered a useful tool for the study of wind driven natural ventilation, especially for the assessment of the ventilation rate and of the air distribution inside a room.