Describes experiments conducted in 38x30x7 ft rooms and in a 1/12-scale model building to study the effects of thermal buoyancy, diffuser opening and ventilation rate on room air movement in mechanically ventilated spaces. Finds that the decay rate of the diffuser air jet and the average air velocity in the reverse flow, which included the occupied zone, were linearly correlated with the Archimedes number.

KEYWORDS: Air flow, experiment, rooms, diffusers, buildings, models, ventilation air jets, mechanical ventilation, ventilation, Archimedes numbers.