An investigation of the influence of nozzle aspect ratio on the velocity field of turbulent plane jet

Abstract

The effect of nozzle aspect ratio (w/H) (major axis to minor axis ratio) on the velocity field of a turbulent plane jet is investigated using a hot-wire anemometer. The aspect ratios investigated were in the range 10 < w/H < 60. The initial turbulence intensity proles exhibit a lower intensity at higher aspect ratios although this is probably caused by the nozzle whose proles change with aspect ratio. The length of the potential core and the normalized mean and rms velocities are all found to be a function of wH, in both the near and far field. Lower aspect ratio leads to faster decay of the mean velocity. Most investigations on aspect ratio effects have been on rectangular jets, hence this work is unique in its own right. Overall, the dependence of the current plane jet on aspect ratio is quite significant.