Velocity and concentration characteristics and their cross correlation for co-axial jets in a confined sudden expansion. II - Predictions

Measurements of coaxial jets in a confined sudden expansion were performed; the geometric parameters of the experiment were appropriate to the aircraft gas turbine combustor and the two-equation turbulence model. This paper gives the prediction of this flow made with a mathematical model. Predictions and comparisons with the experimental data include radial profiles of time-averaged axial velocity, radial velocity, mixture fraction, and their fluctuations, kinetic energy of turbulence, turbulent shear stress, and turbulent mass flux. Qualitative agreement was obtained for all variables. Earlier recommendations concerning a lower turbulent Schmidt number than normally used are confirmed, and the assumption of a constant Schmidt number across the flow appears to be adequate for the calculation of time-averaged scalar quantities.