This study has been performed as a complement to the graduate studies of Yonghui Jin at the National Institute of Occupational Health and the Royal Institute of Technology. It was initiated by the need to analyze free convective flows along vertical walls within the test chamber employed for experimental work with particle transport in turbulent buoyant plumes.

 Natural convection in a thermally driven square cavity filled with air is studied numerically. Since the thermal Rayleigh number of the configuration ranges between 108 and 1012, the flow is turbulent and k-& models are used to predict the behavior of the flow. For this natural convection problem, the viscous sublayer must be discretized and the behavior of the turbulent quantities is damped within this sublayer through low-Reynolds number modelling.

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.