Plane-Air-Jet Corner Zone Modelling in a Room Ventilated by an Active Chilled Beam

Recent studies have demonstrated the influence that air jets in rooms ventilated by chilled beams have on draught-related thermal sensation. The most critical zone in which people often suffer draught sensation is located near a wall and close to the floor. To avoid the draught sensation, the critical velocities of the returning air jet should be specified and determined before the jet enters the occupied zone. In this study, the velocity of the attached plane jet was modelled and measured at six heights and at eight different distances from the wall. Results showed that the returning corner airflow reattaches to the floor surface with entrained ambient air after separation from the wall. The maximum returning air velocity was found to be close to the floor surface. Air in the rest of the room air was shown to move, rather than remain still. Moreover, the moving room air does enforce free shear at the free boundary of the attached jet. This new model could be applied to estimate the possibility of draught risk and to predict the returning airflow velocity within the occupied zone at the most critical corner region.