EXPERIMENTAL-STUDY OF A TURBULENT CROSS JET

The turbulent characteristics of a cross jet mixing flow have been measured after the geometric cross point of the centerlines of the two nozzles. The flow has been generated by two circular nozzles and the crossing angle of the jets was fixed at 45 deg with respect to each other. The flowfield is strongly influenced by the cross point stagnation region, which creates an elliptical jet region with unusual turbulence properties. The measurements have been carried out at two Reynolds numbers, Re = 5.2 and 6.5 ×l 104, and some influences of nonsimilarity have been studied. The major measurement system consisted of a two-channel hot-wire anemometer connected to an on-line computer system. The measurement of the mean velocities and the Reynolds stresses have been compared with existing semiempirical relationships for jet flows, and the comparisons have proved useful in understanding the flow structure. The general shape of the jet retained an elliptical cross section in the downstream direction and the spreading rates have been measured and curve fitted with semiempirical expressions. Also measured were the statistical distributions of the flatness factors along both the Y and Z axes, and the resulting distributions were similar to single jet flows across the central portion of the cross jet. The outer region of the flow exhibited a large amount of scatter for the majority of the statistical measurements that have been carried out. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.