A use of sensitivity analysis in k-epsilon turbulent round jet modeling

It is shown that sensitivity analyses can be used to systematically understand the structure of the k-epsilon model applied to a complex flow. In applying that analysis to round jet flow, it is found that the flow is strongly dominated by the jet conservation of momentum. All sensitivity coefficients relating to density and velocity show similar behavior because of the conservation constraint, and almost all of the parameters of the model can be used to some degree to correct the round jet spreading rate. Density variation has a surprisingly weak influence on the structure of the k-epsilon mode. There were no major qualitative changes in the behavior of the sensitivity coefficients with density variation except near the jet boundary. Near the initial region of a round jet flow, the model is very sensitive to the parameters on which it depends. This sensitivity occurs throughout the jet and is maximum at the boundary.