Flow modeling in a bend of a natural river based on different turbulence models(case study:Doab Samsami River)

Flow modeling in rivers is very complicated due to their meandering path. Therefore, the use of an accurate numerical model for predicting flow pattern and the effects of flow turbulence is necessary. Furthermore, choosing the type of turbulence model can be effective in simulating and studying flow properties. Different types of turbulence models can be used in SSIIM numerical model. In this study, with the aim of investigating the efficiency of turbulence models, three different kindes of k-Ԑ turbulence model,including the standard type, based on water velocity and RNG, are used to simulate flow characteristics in different points of a 45 degrees cross-section from a steep bend located on the Doab Samsami river. Comparing the measured values of the velocity component with the results of the model indicated that the standard k-Ԑ model for determining the vertical component of velocity and k-Ԑ model based on water velocity for the longitudinal component of the velocity are best models in accuracy, respectively and generally the ability of all mentioned the turbulence models evaluated well. Moreover, exact consideration of bed roughness and roughness of the channel bank in the numerical model can have a significant effect on the accuracy of the model results.