Preliminary examinations of a 'Round Jet Initial Condition Anomaly' for the k-epsilon turbulence model

The current numerical study assesses the capability of the k-ε (epsilon) model to predict downstream trends of round jets with varying initial conditions. The numerical model was compared with experimental data for three jets issuing from a smooth contraction, a sharp-edged orifice and a long pipe respectively. The results show that, while the initial conditions are similar, the downstream trends predicted from the model are opposite to those obtained from experiments. This is deduced to follow from the fact that two-equation models do not account for the effect of large-scale coherent structures, and thus provides further evidence that the turbulence "constants" are not universal