Publication date: January 2014
Source:Building and Environment, Volume 71
Author(s): S. Nabi , M.R. Flynn
When a common rectangular barrier between two zones with slightly different densities is partially removed mimicking the sudden opening of a door, a two-layer exchange flow develops and two qualitatively different, though highly coupled, kinds of flow are observed to either side of the barrier. In the zone that initially contained the dense fluid, a buoyant plume ascends resulting, over time, in a vertical density stratification through a filling-box process. Depending on the geometric parameters two scenarios are possible. Either the terminal position of the first front lies above the bottom of the barrier, or it lies below. Special attention is devoted to the latter case, which is favored for large doorway heights and when the zone that initially contains the dense fluid is comparatively small in volume. The associated complications are (i) the nature of the exchange flow changes once the downward-propagating first front surpasses the bottom of the barrier, and, (ii) the terminal stratification in the zone that initially contains the light fluid contains an intermediate layer in which the density varies continuously with height. We also present a model that presumes that both zones remain well-mixed. Similitude experiments help to identify the limitations of both categories of analytical models discussed above. The implications of our results on the design of buildings that exploit heat gains by attached solaria are discussed.
Source:Building and Environment, Volume 71
Author(s): S. Nabi , M.R. Flynn