PIV measurement of the attached plane jet velocity field at a high turbulence intensity level in a room

Abstract

The behaviour of an attached plane jet at high turbulence intensity (>20%) is not completely understood, especially at relatively low Reynolds numbers (<2000) in a room. This study focuses on the detailed mean and instantaneous jet flow field using the particle image velocimetry (PIV) measurement technique in a full-scale climate chamber. Three isothermal conditions at different Reynolds numbers based on the jet slot height and slot average velocity, 960, 1320 and 1680, were measured, having a turbulence intensity of 44%, 30% and 22%, respectively. The results show that the measured jet velocity was able to match the earlier empirical turbulent jet results when the turbulence intensity was of the order of 40%. Incomplete self-similarity occurs when the turbulence intensity is less than 30%. After a few slot heights downstream from the jet slot, most of the data of the jet at the Reynolds number 960 present self-similarity characteristics.