The Merging of Two Unequal Axisymmetric Parallel Turbulent Jets

Results of an experimental study of the merging of unequal parallel round turbulent jets are presented. Experiments were conducted for a jet axial separation to nozzle diameter ratio of 3.0 and the Reynolds numbers ranging from 8 000 to 15 000. The distance to the point where the jets are merged was measured for a range of jet source momentum flux ratios. Three different merger criteria were used based on the mean velocity profile, mean passive tracer concentration profile, and Reynolds stress profile. The results show that the concentration profile merges closest to the jet sources followed by the velocity profile with the Reynolds stress profile merging furthest from the nozzles. For all three profiles the merge distance is relatively insensitive to the momentum flux ratio, consistent with previous findings for slot jets and buoyant round jets. The measured merge distances are consistent with previously published results for equal round jets, though the poor spatial resolution of data in the literature means that limited comparison is possible. There are no studies of unequal jet merger currently in the literature that could be used for comparison.