Evaluation of turbulent models in sudden expansion analysis at High Reynolds numbers

Using abrupt expansion as an energy dissipater in bottom outlet of dams may have unfavorable effects on dam safety due to cavitation. Domain and intensity of cavitation, depends on magnitude and location of negative pressure. Therefore predicting the extent and intensity of negative pressure plays an important role in detection of cavitation. On the other hand, there is no globally accepted turbulence model to predict negative pressure. In this paper an experimental investigation has been performed to determine the variation of pressure. Different turbulent models were ranked through the comparison of analytical and experimental results. It was found that the Realizable ε − k model has better prediction with respect to the others. Key-Words: Computational Fluid Dynamics, Turbulent models, sudden expansion, wall-pressure, energy dissipation, cavitation.