Published online by Cambridge University Press: 26 April 2006
The structure of the far-field turbulent region of an incompressible free jet developing downstream of an axisymmetric nozzle is studied by means of the Reynolds time-averaged equations. The analysis employs the method of matched asymptotic expansions, with limit-process expansions developed in the limit of large Reynolds number. The analysis reveals the existence, far downstream of the nozzle exit, of a turbulent core region, an irrotational exterior region, and a distinguished intermediate region. Self-similar formulations are sought for all three regions in terms of appropriate independent and dependent variables. The stress- and pressure-function solutions for the exterior region, unlike the mean-velocity solutions, represent new information on the far-field flow behaviour. The analytical results of the centreline decay of the mean axial velocity and those of the radial distributions of the axial and radial mean-velocity components and the shear- and normal-stress components are compared with available experimental data.