Journal of Water Sciences Research: 1 (2)

Open Access Article

1 - Sensitivity analysis of geometric and hydraulic parameters on water depth of flood plain in the AbNik River
Akram Gashtasebi Mohammad Reza Pirestani

Transfer of debris flow caused by floods in the river downstream of the mountains leads to several damages every year. Numerous researches have been carried out on the Mountain Rivers the results of which show the importance of performing more researches to control debr More

Transfer of debris flow caused by floods in the river downstream of the mountains leads to several damages every year. Numerous researches have been carried out on the Mountain Rivers the results of which show the importance of performing more researches to control debris flows in the floodplain because of various effective hydraulic-geometric parameters.For this purpose, AbNik Mountain River located in Jajrood basin, northern Iran was selected to evaluate the effect of geometric and hydraulic parameters on moving and controlling the debris flows. Therefore, a length of 200 meters of the steep mountain river length was chosen for which velocity values were measured at different times and at different levels. In 28 selected sections, bed materials were sampled and mapped. Using the analytical methods for field data measurement and geometric properties of the composite trapezoidal channels and hydraulic equations such as Manning, sensitivity analysis of different geometric- hydraulic parameters was performed. In this analysis, using Manning equation in the composite trapezoidal channels, a multivariate equation was obtained by which the flow depth is obtained using trial and error analysis method (Newton-Raphson equation), i. e. variations of each parameter with respect to flow depth in the flood plain are obtained by keeping the other parameters constant at the minimum value. Changes of the geometric and hydraulic parameters were plotted versus flow depth. Results were obtained by investigating the resulted diagrams and equations. Analysis of the results showed that the longitudinal slope of the channel and width of the channel floorhad the greatest effects on the flow depth in the flood plain of the Mountain Rivers. Manuscript profile

Open Access Article

2 - Experimental Study of the Effect of Hydraulic Parameters on Debris Flow Control in Inclined Slit Trapezoidal Check Dams
Arash Razmkhah Mohammad reza Pirestani Amir Ebrahimi Fardshad

Check dams are one of the structures used to control debris flows. In this study, in order to evaluate the effect of hydraulic parameters on debris sediment trapping rate by the slit trapezoidal check dams with different angles, and to develop an empirical relation for More

Check dams are one of the structures used to control debris flows. In this study, in order to evaluate the effect of hydraulic parameters on debris sediment trapping rate by the slit trapezoidal check dams with different angles, and to develop an empirical relation for determination of trapping coefficient of the dam reservoirs, three physical models of the check dams were used. The tests were performed on a shapeable flume with 15, 20 and 25 ° slopes, under 20, 25 and 30 liters per minute flow rates, 60, 75 and 90 degrees of check dam angles to the horizontal and for a sediment aggregate with a non-uniform gradation. By determination of the effective dimensionless parameters, the effect of these parameters on debris sediment trapping rate was evaluated by plotting diagrams. The analysis of experiments showed that, the trapping rate of the check dam increased by decreasing the channel slope, increasing the check dam spillway height and decreasing the check dam angle. Different relations were evaluated using linear and non-linear multivariate correlation analyses of dimensionless parameters, and a multivariate relation for determination of the sediment trapping coefficient was proposed. Manuscript profile

Open Access Article

3 - Simulation of water surface profile in vertically stratified rockfill dams
Puria Asiaban Ebrahim Amiri Tokaldany Mohsen Tahmasebi nasab

Detention rockfill dams are accounted as economically efficient structures for flood control, river bed and banks protection, flow diversion, etc. As the hydraulic behavior of these structures, when are used for flood control, is affected by the depth of water in their More

Detention rockfill dams are accounted as economically efficient structures for flood control, river bed and banks protection, flow diversion, etc. As the hydraulic behavior of these structures, when are used for flood control, is affected by the depth of water in their porous media, there is interests to predict water surface profile through the body of these structures. In this research, we developed a numerical model for prediction of the water surface profile in heterogeneous (stratified) detention rockfill dams. The new model is a modified form of gradually varied flow (GVF) equation which has been solved by direct step method and can also be applied to the flood routing. To validate the numerical model, a set of laboratory experiments has been conducted and the results were compared with those provided using the numerical model. As the maximum mean error is determined as 17.6%, it is found that the introduced model gives satisfactory results and it can be used to determine the water surface profile, and consequently, computing flood routing Manuscript profile

Open Access Article

4 - Assessment of Turbulent Models in Computation of Strongly Curved Open Channel Flows
Omid Seyedashraf Ali Akbar Akhtari

Several rigorous turbulent models have been developed in the past years and it can be seen that more research is needed to reach a better understanding of their generality and precision by verifying their applications for distinct hydraulic phenomena; under certain assu More

Several rigorous turbulent models have been developed in the past years and it can be seen that more research is needed to reach a better understanding of their generality and precision by verifying their applications for distinct hydraulic phenomena; under certain assumptions. This survey evaluates the performance of Standard k-ε, Realizable k-ε, RNG k-ε, k-ω and RSM models in predicting flow behavior in a strongly curved open channel bend. Accordingly, three-dimensional numerical simulations were carried out using a state-of-the-art computational fluid dynamics code, ANSYS-Fluent14, which employs finite volume method to solve the respective governing equations. The models’ accuracy were analyzed and compared with observed data from experimental studies on a 90° open channel bend. The results indicate that although the RSM model can precisely capture all the flow characteristics in a strongly curved open channel flow, the Standard k-ε model may be considered as slightly less accurate yet much faster model. Manuscript profile

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