Y. Aminpour; M. Yasi; J. Farhoudi; H. Khalili Shayan
Abstract
The development of an enhanced approach for the use of radial gates as flow measurement structures is important in irrigation networks. In this study, new theoretical relationships were developed to estimate the discharge coefficient (Cd) for a single radial gate with three different sills, at free and ...
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The development of an enhanced approach for the use of radial gates as flow measurement structures is important in irrigation networks. In this study, new theoretical relationships were developed to estimate the discharge coefficient (Cd) for a single radial gate with three different sills, at free and submerged flow conditions. These equations were calibrated and verified by using about 2600 laboratory data from the world-wide literature. Results indicated that the flow rate under the radial gates can be estimated by an error in the order of ±5%. The reliability of the proposed relationships and in particular the scale effects, were tested using 530 field data of radial gates operating on different canal networks. The predictions of the flow rates from the proposed method are shown to be superior compare with the other predictive methods. In the presence of multi radial gates in a given cross section, the total discharge is estimated by an error up to ±30% when using single radial gate relationships. This discrepancy is considered to be mainly due to the influence of different gate openingsand the difference between gate and canal widths. A self-developed correction factor, k, was introduced to account for the dimensionless effective parameters such as the ratio of gate-to-canal width, the geometry of the gates, and the ratios of upstream and downstream depths to the average gates openings. The results are promising the predictive errors of the total flow rates are reduced by ±5% and ±10% for 74% and 94% of the flow data, respectively.
M. Nasrabadi; M.H. Omid; J. Farhoudi
Abstract
Abstract
In this study, the effect of suspended load transport on the characteristics of submerged hydraulic jump (SHJ) in a rectangular channel was investigated experimentally. Sediment concentration and jet Froude numbers in the range of 0.424%-16.15% and 1.93-4.96, respectively, were considered. ...
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Abstract
In this study, the effect of suspended load transport on the characteristics of submerged hydraulic jump (SHJ) in a rectangular channel was investigated experimentally. Sediment concentration and jet Froude numbers in the range of 0.424%-16.15% and 1.93-4.96, respectively, were considered. Tow grain size 0.15 and 0.03 mm were used in the experiments. Characteristics of submerged hydraulic jump including velocity and concentration distribution, length of jump, the submergence depth on the gate and the energy dissipation were studied. The results showed that the submergence depth on the gate and the energy dissipation are constant by increasing of sediment concentration. The length of the jump at the presence of suspended sediment is smaller than those due to clear water flow. Also, suspended sediment by decreasing of flow resistance is made to decrease flow velocity.
Keywords: Submerged hydraulic jump, Sediment concentration, Length of jump, Velocity distribution
