Wind catchers are natural ventilation systems attached to buildings in order to ventilate the indoor air. In order to design and evaluate the performance of wind catchers, as a natural ventilation system, an accurate CFD simulation of indoor airflow and outdoor wind flow is fundamental. It is widely known that there are a large number of computational parameters influencing CFD simulations. Consequently, comprehensive sensitivity analyses of the effect of these parameters on the simulation results are essential to provide guidance for the evaluation of a CFD study. According to the literature review carried out, a wide generic sensitivity study for the CFD simulation of natural ventilation in wind catchers is highly required. This paper presents a series of 3D steady RANS simulations for a generic isolated two-sided wind catcher attached to a room subjected to wind directions ranging from 0º to 90º with an interval of 15º. The CFD simulations are validated with detailed wind tunnel experiments. The influence of an extensive range of computational parameters is explored in this paper, including the resolution of the computational grid, the size of the computational domain, the turbulence model and the order of the discretization scheme.

Performance of four-sided wind catcher was investigated by numerical method. Wind catcher is one of the vernacular elements which are widely used in hot, hot-dry and hot-humid climates especially in Middle East countries. They are tall towers on the building's roof top with several vents to catcher wind for cooling the interior spaces. In this study six 3D rectangular wind catchers with different channel height were employed based on the review of the wind towers' characteristics with emphasis on their morphology and categorization of the wind towers based on their physical attributes and parameters. In this study also CFD simulations were accomplished to evaluate the effect of height on ventilation rate of wind catcher room. It was found that the height of wind catcher influence the ventilation rate, wind velocity and volume flow rate on different opening of the wind catcher. Generally, wind velocity on windward increased and ventilation rate of room decreased by increasing the wind catcher height.