Wind Tunnel and CFD Investigation of the Performance of a Wind Driven Ventilation System

Experimental investigations and CFD simulations were carried out to evaluate the performance of square and circular section wind - driven systems for natural ventilation application in buildings. Wind tunnel and smoke visualisation tests were conducted on a full-scale model based on a commercial wind catcher design. The experimental set-up consisted of each system being connected to a model test room. The devices were divided internally into four quadrants/segments for the purpose of air supply and extract. Pressure coefficients distribution, internal air speed and volumetric air flow rate were measured for various wind speeds and for different wind directions. In addition, CFD simulations were carried out to obtain the pressure distribution and air flow pattern around the square section system. The results show that the performance of the devices depends mainly on the speed and direction of the prevailing wind. Although the ventilation rate increases with wind speed it was found to decrease with the increase in the wind direction angles from 0 to 45, measured from the normal to the face of the system.