A comparison of predictions by SST and Wilcox κ-ω models for a Mach 0.9 Jet

Numerical simulations of Mach 0.9 axi-symmetric turbulent jet using the Shear Stress Transport (SST) and Wilcox κ - ω models have been carried out using FLUENT. The axi-symmetric calculations have been done on a structured mesh with approximately 50000 and 200000 cells. For comparison, a 3D simulation with 1 million cells in a 60° pie sector has also been carried out using the SST κ - ω model. The numerical predictions have been compared with experimental data available in the literature. Axial variation of the mean axial velocity, axial variation of turbulence intensity, self similarity profiles, radial variation of u′,ν′, u′ν′ and frequency spectra are compared. The potential core length is predicted better by the SST model, whereas the predicted centerline velocity decay is better forWilcox model, and faster than the measured value for both models. In general, the disagreement between the predictions and the experiments is more for the Wilcox model, particularly for centerline velocity and turbulent intensity. There is very little difference in the predictions of the SST κ - ω model using the baseline and the fine mesh. On the contrary, predictions of the Wilcox κ - ω model exhibit considerable variation between the two meshes. The present calculations show that the SST κ - ω model can predict mean, turbulence quantities as well as trends in acoustic quantities reasonably well. Copyright © 2008 by V. Babu.