Published online by Cambridge University Press: 26 April 2006
The paper formulates the concept of a semi-preserving developing of a free nonisothermal swirling jet. On the basis of experimental data it may be estimated that the semi-preserving conditions are established at the distance x − x0 ≈ (15−20) D. Also, it has been pointed out that self-preservation, which requires the turbulence structure to be similar during decay, may be considered as an asymptotic state of the semi-preserving development achieved in practice at a distance where $\overline{u_r u_{\phi}/ \overline(u_x u_r) \ll 1\cdot 0$.