Coaxial jets of different mean velocity ratios, part 2

Abstract

This second part of the investigation presents the flow characteristics of coaxial jets of mean velocity ratios (inner to outer) 0·15 < λ â 1 < 1. An attempt to correlate data between coaxial jets and its limiting cases of a single jet and an annular jet has been made. The flow structures originating from each of the mixing regions are investigated. For the coherent structure in the outer mixing region a comparison with that of the single jet is attempted. For the inner coherent structures (identified as coflowing-wake-vortices), investigations into their dependence on λ â 1 is also made. The inner potential core length, and hence the elongation function, is shown to play an important role in correlating data from coaxial jets of different λ â 1 . At low λ â 1 , coalescence of the coflowing-wake-vortices and their evolution into another train of vortices that resembles the wake-vortices found in the annular jet emphasizes the role of the coaxial jet as an intermediary between the single jet and the annular jet. © 1987, Academic Press Inc. (London) Limited. All rights reserved.