An experimental investigation of the near-field region of free turbulent round central and annular jets

摘要

The present study is an experimental investigation of two limiting cases of coaxial turbulent jet namely the round centra1 jet and the annular jet, using Laser Doppler Anemometry. The results of the round jet are presented and discussed for twoexit mean velocities. While the annular jet is tested for one exit velocity. The variations along the jets centerlines and the radial I profiles for mean and fluctuating longitudinal velocities are presented. In addition a comparison between the presentresults and the corresponding results of other investigators are also included. The obtained data revealed that the results of the turbulent central round jet are in a general agreement with those of the previous investigators. Meanwhile, the results ofthe annular jet followed the same trend as the results of the previous investigators with differences in magnitudes due to the high turbulence intensity at the exit of the present tested jet.