Numerical analysis of ventilation flow through a three dimensional room fitted with a two-sided windcatcher

A windcatcher is a structure fitted on the roof of a building for natural ventilation; it extracts the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building and using ventilation principles of passive stacks and wind tower, respectively. In this paper, air flow through a three-dimensional and real-sized room fitted with a two-sided windcatcher is investigated numerically, using a commercial computational fluid dynamics (CFD) software package. The standard K-ε turbulence model is used. Flow pattern and flow velocity are considered in terms of some of the key factors on the performance of a typical windcatcher such as the windcatcher's location, the shape of the windcatcher's bottom, inlet velocity, and the length of the windcatcher's bottom. It is found that the windcatcher's shape at its bottom strongly affects flow pattern and flow velocity when inlet velocity is not too low. This leads to a way of developing the windcatcher's effectiveness in ventilating the living area (lower part) of a room