جستجوی مقالات مرتبط با کلیدواژه « quasi two-dimensional modeling » در نشریات گروه « آب و خاک »

In this study, the calculation of hydraulic flow and sediment (suspended load and total load) of Zaremrood river located in Mazandaran province has been investigated using Shiono and Knight quasi-two-dimensional model. This model is based on the Navier-Stokes continuity and momentum equations and is simplified by depth averaged concept. For this purpose, using the finite element method, this model was solved numerically and the lateral velocity distribution were calibrated at the Garmrood hydrometric station. Comparison of obtained results by Shiono and Knight model in different flow discharges against measured data indicates the high accuracy of the model for lateral velocity distribution. Afterward, by using the computed lateral velocity distribution, the distribution of suspended load and total load across the river was simulated. The results showed that among the 5 empirical suspended load equations selected in this study, the Einstein formula (1950) has the best accuracy in both one and quasi-two-dimensional modeling cases. This relationship in one-dimensional state with standard deviation of discrepancy ratio of 0.56% has a higher accuracy than the Rouse (1937) and Brooks (1963) sedimentary relations with a standard deviation of 0.52% and 2.47%, respectively. Finally, among the 5 experimental relationships of the total load studied, Meyer-Peter-Muller (1973), Ackers-White (1973) and Engelund-Hansen (1967) sedimentary relationships with discrepancy ratios of 66.67, 41.67 and 16.67, respectively presented the best results in one-dimensional mode, and the accuracy of all three methods was better in two-dimensional mode than in one-dimensional mode. Finally, it was found that the accuracy of suspended load and total load modeling in quasi-two-dimensional mode is more than one-dimensional, which shows the high impact of Shiono and Knight model in simulation of hydraulic flow and sediment.

Determining the amount of sediment carried by rivers is important in several ways. This parameter is effective in design of dimensions and geometric characteristics of flow regulation and diversion structures, reservoir dams as well as pumping stations. In this study, the calculation of flow discharge and bed load of Zaremrood river located in Mazandaran province has been investigated using Shiono and Knight quasi-two-dimensional model. This model is based on the Navier-Stokes continuity and momentum equations and has been simplified by depth averaged concept. For this purpose, using the finite element method, this model was solved numerically and the lateral velocity distribution was calibrated at the Garmrood hydrometric station. Comparison of obtained results by Shiono and Knight model in different flow discharges against measured data indicates the high accuracy of the model for lateral velocity distribution. Then, by using the computed lateral velocity distribution, the distribution of bed load across the river was simulated. The results showed that among the 17 empirical bed load equations selected in this study, the Duboy formula (1879) has the best accuracy in both one and quasi-two-dimensional modeling cases. In 1D modeling case, this formula with standard deviation of the discrepancy ratio of 0.34 percent had better agreement with the measured bed load in comparison to the Frijlink (1952) and Meyer-Peter and Mueller (1948) equations with the standard deviation of 3.46 and 7.32 percent, respectively. In 2D modeling bed load transport, the root mean square error (RMSE) was obtained 7.45, 98.8 and 172.9 for three equations of Duboy, Frijlink and Meyer-Peter and Mueller, respectively which indicates that only Duboy formula has an acceptable accuracy while Frijlink and Meyer-Peter and Mueller equations have large errors. The results also showed that the bed load transport in quasi-two-dimensional model using Duboy equation is more accurate than one-dimensional case.