Experimental investigation of plane jet flowfield characteristics

Abstract

Flowfield characteristics of plane jet was investigated experimentally. A rectangular nozzle exit was employed. Two boundary conditions were tested such that the contribution of entrainment was demonstrated. The influence of Reynolds number was displayed. The experimental program included survey of the potential core region. The jet flow field characteristics were interpreted in the context of velocity and turbulence measurements. Those measurements were taken along several sections downstream the jet exit. When compared with the similarity theoretical analysis deduced from Prandtl's mixing length theory, the experimental findings of the mean velocity were found to comply well with the theoretical predictions. The linearity relationship established theoretically between the half-jet-width and the streamwise location was also satisfied experimentally. In the fully developed flow region, higher levels of turbulence were attained at lower Reynolds numbers, and the maximum fluctuations were observed close to the jet exit. Within the potential region, the flowfield was insensitive to changes in the nozzle boundary. The turbulence level in the entrainment flow field was 5.6% of the mean velocity.