Numerical prediction of axisymmetric free shear flows with a second-order Reynolds stress closure

The paper deals with the application of the Reynolds stress closure to the calculation of the axisymmetric jet in stagnant surroundings with and without swirl. A technique for handling the numerical solution of the equations with the Patankar-Spalding two-dimensional parabolic scheme is first presented including a practice for reducing the sensitivity of the solution to the forward step. Solutions to the round, non-swirling jet display a rate of spread that is 50% too large when constant coefficients, optimized for plane flow, are used. The origin of the discrepancy is shown to be the source terms in the dissipation rate equation, a 1% change in either of the source-term coefficients altering the rate of spread by about 4%.