Evaluation of turbulence closure models for the simulation of circular impinging jets

This study examines application of two-equation turbulence closure models for simulation of the Jet Erosion Test (JET) used to evaluate soil erodibility. Four turbulence models were examined: standard, Re-Normalization Group (RNG), and Realizable k-e, and Shear Stress Transport (SST) k-co. It was found that all models except the standard k-e ovcr-prcdict the potential core length due to under-prediction of mixing in this region. This prediction was improved by specifying a higher turbulence kinetic energy for the nozzle boundary condition. The models also were unable to correctly simulate the developed free jet region. A turbulence damping procedure was employed for the SST model that helped improve the velocity prediction in the near-field. However, the velocities in the far-field and impingement regions were still over-estimated, and an excessive turbulence buildup was observed in the impingement region. This study shows that two-equation models are not reliable for predicting the impingement region of a circular jet.