Air Movements through Horizontal Openings in Buildings - A Model Study

A building contains a number of large openings, such as doors and staircases. When the temperature of the spaces connected by these openings differs, the difference in density will cause air movements through them.Horizontal air movements through vertical openings in buildings, such as doors and windows are wellinvestigated while studies of air movements through horizontal openings, such as stairwells are less frequent and therefore this work focuses on this case. This paper reports on an experimental study of the possibility of using buoyancy forces to distribute air and heat through horizontal openings. The experiments have been carried out in a scale model with water as the operating fluid. The result of the study shows that the flow rate through a horizontal opening is approximately half of the flow rate through a vertical opening for the same conditions, probably caused by the more complex flow pattern in the horizontal opening. A staircase below the horizontal opening will guide the flow somewhat and will cause a small increase of the fluid exchange through the opening.