Simulation of two-dimensional velocity distributions in rivers based on Chiu's theory (Case study: Gorganrood River)

Solution of stream-wise flow velocity on two dimensions (in width and depth directions) in rivers is essential for many hydraulic features such as stage-discharge rating curve development, suspended sediment transport estimation and boundary shear stress calculation. In this paper based on Chiu's entropy theory, a simple method has been proposed for simulation of vertical and transverse profiles of flow velocity in the straight rivers. For calibration and validation of the proposed method, a new idea based on the optimum estimation of entropy parameter in rivers was used. The results of this study at Aghghalla hydrometric station located on Gorganrood River showed that velocity flow field obtained by the Chiu's theory has suitable accuracy compared to the field data. Further, statistical analysis of the results revealed that the mean absolute errors of this method for solution of flow velocities in calibration and validation stages are 5.2% and 3.5%, respectively. These errors are 5.9% and 6.04% respectively for the total river flow discharge prediction. According to the few required input data, the proposed method has more advantage than other existing methods.