Influence of the magnitude of the two initial velocities on the flow field of a coaxial turbulent jet

The present investigation is a continuation of a program to study the effects of various parameters on the flow field of a coaxial turbulent jet. In the present study the effect of varying the absolute value of the two initial axial mean velocities of the jet is investigated experimentally, while keeping their ratio constant. The effect of absolute value of each stream velocity, on the flow field, was investigated by means of achieving the velocity ratio, lambda =U-i/U-o=2, three times with two different velocities each time. Moreover, The similarity of the axial mean velocity profiles was investigated, for two other values of lambda =3.3 and 4.5, and compared with the results of the single jet. The results show that the reduction in the absolute values of the velocities of both streams while keeping the same velocity ratio constant made the coaxial jet decay faster along the centerline. In addition, similarity of the radial profiles of the axial mean velocity was obtained in the fully merged region. (C) 2001 Elsevier Science Ltd. All rights reserved.