Hadi Shams Nia - Msc. Student, K.N. Toosi University of Technology, Tehran, IRAN
Kourosh Hejazi - Assistant Prof., K.N. Toosi University of Technology, Tehran, IRAN

The commonly used linear k-ε turbulence model is shown to be incapable of accurate prediction of turbulent flows where non-isotropy is dominant. One example of non-isotropic flows which is due to stratification and consequently variation of density through vertical layers is saline water flow. In this paper a nonlinear k-ε turbulence model firstly presented by Speziale (1986) is implemented in the existing hydrodynamic model. The hydrodynamic model solves the fully nonlinear Navier-Stokes equations based on an ALE (Arbitrary Lagrangian Eulerian) description. The model is an extension to WISE (Width Integrated Stratified Environments) 2DV numerical model, originally developed by Hejazi (2004). The simulation results have been compared with the experimental data and have shown acceptable agreements. The predictions are also compared with the results of the original model employing a standard buoyant k-ε turbulence model, which show the advantage of the new model in prediction of non-isotropic flows.

Nonlinear k-ε turbulence model, Stratified flows, Salinity, non-Isotropic turbulence model, Gravity currents