Experimental Investigation and Modeling of the Attached Plane Jet Velocity Development Characteristics in the Transition Process in a Room

Attached plane jets are widely used in room-air distribution solutions. The turbulent attached plane jet behavior in the transition process that determines the jet behavior in the fully developed region is not completely understood, especially at relative low Reynolds numbers (<6000). This study focuses on obtaining the detailed jet mean flowfield velocity data and jet growing characteristics in the transition region. A virtual origin model was set up to predict the maximum jet velocity decay, and the experiment was carried out to validate the model. In this experiment, three Reynolds numbers-1000, 2000, and 4000-were tested at different distances from 2 to 30 slot heights downstream of the jet slot. The results are significantly different from the known theory for the third and fourth jet zones definition. The experimental data show that after six slot heights downstream distance, most of the data start to fit closely the fully developed turbulent jet velocity profiles and present self-preserving characteristics earlier than in previous studies. The maximum velocity calculated by the models showed good agreement compared with the measured data at distances of 10 to 30 slot heights.