TRANSIENT BEHAVIOUR OF INDOOR THERMALLY STRATIFIED AIR FLOW –– (1) CAPTURING THE OSCILLATORY MOTION

摘要

Indoor stably, thermally stratified flow is one subject of significance in the area of building environment, which represents some key indexes for thermal comfort and indoor air quality. This paper defines the stable stratification of indoor air flow and illustrates the development of penetrative convection in a typical room. Numerical methods with validation by experimental data are applied to figure out the transient behaviour. A simple two-dimensional test room is used to observe the penetrative convection occurred. Oscillatory motion appears when thermal plume by a localised heat source is much suppressed by the stratification. Significant oscillations are found in the cases of stratification parameter ψ =1.6×10-3 and 2.0×10-3. Oscillatory periods are extracted between the flow time of 2500s~3500s when the oscillations have been stabilized.