Natural Ventilation through Large Openings - Measurements at Model Scale and Envelope Flow Theory

An overview is given of the current position regarding the use of wind tunnel modelling and envelope flow theory for determining natural ventilation through large openings. The overview is, to a large extent, a personal one and is illustrated primarily by recent research carried out in Nottingham, some of which has yet to be published in full. Attention is focused on the following uses of wind tunnels:- direct measurement of time-average ventilation rate; measurement of instantaneous flows in stacks; determination of discharge coefficients for theoretical envelope flow models; assessment of steady and unsteady envelope flow models. These are believed to be the more important areas for research and are reflected in the recent work carried out by the author and his colleagues.