جستجوی مقالات مرتبط با کلیدواژه « سرریز دایره ای » در نشریات گروه « آب و خاک »

A compound sharp-crested weir is often used to measure a wide range of flows with appropriate accuracy in open channels. In this study, experiments were performed to investigate the hydraulic flow through a compound weir of circular-rectangular with changes in hydraulic and geometric parameters in free and submerged flow conditions. The characteristics of the weirs include rectangular spans width of 39 cm, a circular radius of 5, 7.5, and 12.5 cm, and heights of 10 and 15 cm. The results showed that by increasing the radius and height of the Weir, upstream water depth increases around 28.4%. At a constant h/p, the discharge coefficient increases with the increasing radius of the circular arc. Also, in the submerged conditions, the discharge coefficient is less (around 40%) than in the free flow condition, which is due to the resistance of the depth of the created stream against the passage of the flow.

In this study, the discharge coefficient of sharp-crested weirs located on circular channels was modeled using the ANFIS and ANFIS-Firefly (ANFIS-FA) algorithm. Also, the Monte Carlo simulations (MCs) were used to enhance the compatibilities of the soft computing models. However, the k-fold cross validation method (k=5) was used to validate the numerical models. According to the input parameters, four models of ANFIS and ANFIS-FA were introduced. Analyzing the numerical results showed that the superior model simulated the discharge coefficient as a function of the Froude number (Fr) and the ratio of flow depth over weir crest to the weir crest height) h/P(. The values of the mean absolute relative error (MARE), root mean square error (RMSE) and correlation coefficient (R) for the superior model were calculated 0.001, 0.002 and 0.999, respectively. However, the maximum error value for this study was less than 2%.

Compound sharp crested weir for measuring the discharge with reasonable sensitivity and accuracy in a wide range of flow, as appropriate solution can be used. Also the transitional water containing sediment and floating will cause problems in how they function. One of the options that can be used to extend weir-gate combined compound sharp crested weir with gate. The purposed of this research, investigation of combined flow in sharp crested weir in the state of compound weir with circular- trapezoidal- rectangular sections by combining gate with opening height of 1.5, 3 and 4.5cm. Experiments carried out in an experimental rectangular canal with length of 12 meters and width of 5 meters. Based on experimental data the results show that, discharge coefficient in compound weir is in the range of 0.58 to 0.85 and in compound weir- gate is in the range of 0.38 to 0.78. The results showed that for a known head over the weir, the discharge coefficient in compound weir-gate is reduced with increasing the height of the gate.The mean values of the coefficient of determination (R2) and the normalized root mean square error (NRMSE) are 0.96 and 0.06, respectively. The results showed that the use of a linear combination of flow equations in compound weir with circular- trapezoidal- rectangular sections and compound weir-gate, with acceptable accuracy is able to estimate the discharge coefficient.