Numerical Study on Natural Ventilation Characteristics of a Partial-Cylinder Opening for One-Sided-Windcatcher of Variable Air-Feeding Orientations in Taif, Saudi Arabia

Abstract

To provide a clean and cheap source of natural ventilation in windy and arid zones, a windcatcher facility is the best option. This paper aims to study the effect of the inlet opening angle of a new windcatcher model with different values ranging from 60° to 90° for three different feeding orientations at leading-down, central-up, and trailing-down locations. The ventilation performance of the new one-sided windcatcher is numerically examined using CFD simulations, where the 3D RANS and k-epsilon equations are applied at different wind speeds. The flow features of the new models are analyzed and compared with a basic traditional model based on the induced air distribution, aerodynamic losses, and ventilation rates. Results revealed that the sharp edge of the inlet opening leads to an increase in the flow separation and recirculation zone, especially when the opening angle is increased. The highest pressure coefficient is achieved by the trailing-down model compared with the other windcatcher models at an opening angle of 90°. The total pressure drop and ventilation rates increase in all the new windcatcher models due to the increase in the opening angle from 60° to 90°. At identical conditions, with an opening angle of 90° and wind speed of 5 m/s, the trailing-down model achieved a higher pressure coefficient than the leading-down and central-up models by 20.55% and 37.37%, respectively. Furthermore, the trailing-down model could provide higher ventilation rates than the central-up and leading-down models by 31% and 42%, respectively. Finally, the trailing-down windcatcher model can be recommended as the best choice to provide natural ventilation at Taif City in Saudi Arabia.