Side Weir Research Articles

Discharge Coefficient of Triangular and Asymmetric Labyrinth Side Weirs Using the Nonlinear PLS Method

AbstractSide weirs are hydraulic control structures widely used in irrigation and drainage systems as well as wastewater treatment plants. These structures also serve as adjusting/diverting flow structures with a minimum head loss. In the present study, by applying experimental data of more than 400 laboratory tests and using the multivariable nonlinear partial least-squares (PLS) method, three nonlinear equations are proposed for discharge coefficient, CM, of triangular and asymmetric labyrinth side weirs. These equations relate the discharge coefficient to the relevant geometrical and hydraulic dimensionless characteristics of flow. Results indicate that the new proposed equations are more accurate compared to those of former studies, being the best tools to estimate the diverted flow discharge over the side weirs.

Predicting trapezoidal and rectangular side weirs discharge coefficient using machine learning methods

Side weirs are useful and common devices in flow measurement issues. These weirs have been extensively used in hydraulic and environmental engineering applications. The characteristic of flow over side weirs are completely different from that over a weir normal to the approach channel. An accurate flow modeling over a side weir mainly depends on the proper estimation of discharge coefficient. In this study, the potential of two different machine learning methods, namely support vector machines combined with genetic algorithm (SVM–GA) and gene expression programming (GEP) were evaluated for predicting trapezoidal and rectangular sharp-crested side weirs discharge coefficient. Correlation coefficient (R), mean normalize error (MNE), and Nash–Sutcliffe index (NS) statistics are used for the evaluation of the model’s performances. The results showed that the SVM–GA model with R = 0.97, NS = 0.94, and MNE = 13% for trapezoidal side weir and R = 0.97, NS = 0.91, and MNE = 18% for rectangular side weir, in test period gives more accurate results than GEP. The results verify that the SVM–GA model can process used data series by better generalization ability and higher prediction accuracy.

Prediction of discharge coefficient of side weir using adaptive neuro-fuzzy inference system

Predicting the discharge coefficient of the hydraulic structures is one of the main subjects related to the hydro-system management. Weirs are the common hydraulic structure widely used in the water engineering projects. Side weir is the common type of hydraulic structure used in water engineering projects. Principal component analysis of the affective parameters on the side weir discharge coefficient leads to develop optimal structure for the empirical formulas and artificial intelligent models. In this paper, the principal component analysis (PCA) technique was used to define the most important affective parameters on the discharge coefficient of side weir (\({\text{Cd}}_{\text{sw}}\)). The result of the PCA showed that the Froude number and ratio of the weir height to the upstream flow depth (P/h1) are the most influential parameters affecting the \({\text{Cd}}_{\text{sw}}\). Developing the adaptive neuro-fuzzy inference system (ANFIS) based on the PCA result showed that the optimal ANFIS structure is related to consider the five and four Gaussian membership function for the Froude number and P/h1 parameters, respectively. The correlation coefficient of the ANFIS model during the training and testing stage was found to be 0.96 and 0.86 correspondingly.

Predictive modeling the side weir discharge coefficient using neural network

Weirs are common structures that are widely used in the almost water engineering projects such as hydropower systems, irrigation and drainage networks along with sewage networks. A side weir has many possible uses in hydraulic engineering and has been investigated as an important structure in hydro systems, as well. In this paper, predicting the discharge coefficient of side weirs ( $$Cd_{sw}$$ ) was considered using the empirical formulas, multilayer perceptron (MLP) and radial basis function (RBF) neural network as delegate of artificial neural network models. The results indicate that Emiroglu formula by correlation coefficient of (R2 = 0.65) and root mean square error of (RMSE = 0.03) is the accurate one among the empirical formulas. Evaluating the performance of the RBF model with ten neurons in the hidden layer involving error indices of (R2 = 0.71 and RMSE = 0.08) showed that this model was a bit better than Emiroglu formula. The structure of MLP model was considered as similar to RBF model whereas the tangent sigmoid was used instead to the radial basis function. The results of MLP model showed that this model with R2 = 0.89 and RMSE = 0.067 had suitable performance for predicting discharge coefficient. Performance of MLP was more accurate compared to RBF model.

Discharge Coefficient of a Circular-Crested Side Weir in Rectangular Channels

AbstractSide weirs are frequently used for water-level control in irrigation systems, sewer networks, and flood protection. Researches on side weirs have generally focused on determining the hydrau...

Improved side weir discharge coefficient modeling by adaptive neuro-fuzzy methodology

In this article, the accuracy of a soft computing technique is evaluated in terms of discharge coefficient prediction of an improved triangular side weir. The process includes simulating the discharge coefficient with the Adaptive Neuro-Fuzzy Inference System (ANFIS). Matlab software is used for ANFIS modeling. To identify the most appropriate input variables, eight different input combinations with various numbers of inputs are examined. The performance of the proposed system is confirmed by comparing the ANFIS and experimental results for the testing dataset. The performance evaluation demonstrates that the ANFIS model with five inputs (Root Mean Square Error (RMSE) of 0.014) is more accurate than the ANFIS model with one input (RMSE = 0.088). The ANFIS model results are also compared with the results obtained from previous regression and soft computing studies.

New Approach for Estimation of Rectangular Side Weirs Discharge in Subcritical Flow

AbstractSide weirs are used to divert the flow from a main channel to a desired environmental area. These basic hydraulic elements are commonly preferred in drainage and irrigation systems of surface water. Many studies have been conducted to determine the outflow discharge of side weirs. De Marchi’s approach, which assumes constant specific energy along the side weir, can be applied to describe the surface equation and therefore the discharge coefficient. However, the use of this approach is not easy in experimental and theoretical studies. This study presents a new semianalytical approach that determines the discharge capacity of rectangular side weirs. The findings of this new method are consistent with numerical and experimental results.

Side Weir Flow on a Movable Bed

AbstractSide weirs are hydraulic structures widely used for flow control in rivers and canals. Whenever the water level rises above the side weir crest elevation, a fraction of the main flow is diverted so that the water discharge flowing downstream in the main channel is reduced. In movable bed channels, the lateral outflow may have significant interactions with the sediment transport processes affecting the side weir flow. The spilled discharge creates a reduction of the downstream sediment transport capacity with a consequent deposition in the side weir proximity. In addition, sediment in the main channel can be diverted into the lateral branch. To investigate these interactions, experimental data at the laboratory scale have been collected and analyzed. The increase of the spilled discharge induced by the local sediment deposition is described according to the classical De Marchi hypothesis. Furthermore, the sediment transport leaving the main channel through the lateral structure is modeled in terms ...

Prediction of side weir discharge coefficient by support vector machine technique

Side weirs have many possible applications in the field of hydraulic engineering. They are also considered an important structure in hydro systems. In this study, the support vector machine (SVM) technique was employed to predict the side weir discharge coefficient. The performance of SVM was compared with other types of soft computing techniques such as artificial neural networks (ANN) and adaptive neuro fuzzy inference systems (ANFIS). While ANN and ANFIS models provided a good prediction performance, the SVM model with a radial basis function kernel function outperforms them. The best SVM model was developed with a gamma coefficient and epsilon of 15 and 0.3, respectively. The SVM yielded a coefficient of determination (R2) equal to 0.96 and 0.93 for the training and testing data. Sensitivity analyses of the ANN, ANFIS and SVM models showed that the Froude number and ratio of weir length to the flow depth upstream of the weir are the most effective parameters for the prediction of the discharge coefficient.

Numerical analysis of subcritical flow over two-cycle trapezoidal labyrinth side weir

The side weirs are basic and effective hydraulic structures utilized commonly in irrigation, flood management, drainage and wastewater systems. The labyrinth side weirs have developed in recent years as more effective and efficient mechanism than conventional side weirs. The multi-cycle trapezoidal labyrinth side weirs could increase the side weir performance. The hydrodynamics of these weirs are considerably sophisticated due to the turbulent flow and vortices in the cycles. This paper presents the hydrodynamic behavior of the side weir with two cycles using Computational Fluid Dynamics (CFD) method. The grid convergence index (GCI) was used to demonstrate the mesh sensitivity in the results, and a fine mesh (9mm) selected relatively among the used meshes was applied to computational volume for more accuracy. As the turbulent model, Reynolds Stress Model (RSM) model, which requires more computation effort, was implemented to consider turbulence effects in more detail. Additionally, certain experimental results were used for verification of the numerical results, and the CFD results were considerably consistent with experimental observations. The detailed hydrodynamic results, which were too hard to determine experimentally, were presented to describe the flow properties of this weir. The results indicated that the discharge coefficient decreased with an increase in Froude number. The best performances were obtained with side weir angle, α=30° and weir height, p=20cm among tested values. The results encouraged the use of computational fluid dynamics methods for the further analyses.

Prediction of Discharge Capacity over Two-Cycle Labyrinth Side Weir Using ANFIS

AbstractPhysical and mathematical models widely used in hydraulic engineering are not always effective in practice. Numerical methods such as the adaptive neuro fuzzy inference system (ANFIS) can be quite useful for estimating the key parameters, especially for complex and multivariate mathematical models. The aim of this study is to determine the discharge coefficients of labyrinth side weirs with two cycles using an experiment setup and ANFIS. Estimation of the discharge efficiency of the side weir has been achieved by using 285 laboratory data sets. The results of ANFIS functions and multiple nonlinear regression (MNLR) analysis were compared with experimental results. It is shown that two ANFIS functions, trimf and gbellmf, give the best estimations, and therefore this technique can be used effectively in practice.

A Comparison on Discharge Coefficients of Side and Normal Weirs with Suspended Flow Load using FLOW3D

Normal 0 MicrosoftInternetExplorer4 Weirs and gates are structures which are used to measure water flow in open channels. Entering rivers’ sediments into channels is considered as one of the main problems in irrigation and water transmission networks. The relations presented based on laboratory results for gates, weirs and apertures’ discharge coefficients have been extracted and developed based on the conditions of sediment free water flow. Therefore, applying these relations in natural conditions requires investigating the effect of suspended load on hydraulic coefficients which are highly effective to technically and economically design and select these structures. The purpose of the present paper was to determine the amount of flow discharge and the type of effective parameters using different geometrical and hydraulic conditions such as overflow height. It was also attempted to present the relation of discharge coefficient at the presence of suspended load. To this end, three-dimensional FLOW 3D model was employed. This numerical model can simulate the flow containing suspended sediments and sediments’ deposition in various parts of channel. In numerical simulation, based on landing number of flow, C d has a determination coefficient (R 2 ) relatively better and higher than laboratory results. It can be attributed to the lack of suspended load thickness distribution in laboratory and difficult conditions of such action in laboratory modeling. In laboratory model, suspended load cannot be fully injected with appropriate ratio to the entire fluid. However, in numerical model, flow thickness amount can be easily added an injected to the model from input boundary on cubic meter unit of flow. This significant point is considered as one of the advantages of numerical model to simulate such problems. In the present study, total relation of flow discharge (C d ) was presented as a combination of values of flow landing (F r ), flow thickness amount (S) and relative low depth (y d /P) in side weirs. st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Calibri; mso-bidi-font-family:Calibri;}

Estimation of discharge coefficients of the broad-crested side weir with various levee's side slope of main channel

Estimation of discharge coefficients of the broad-crested side weir with various levee's side slope of main channel

Numerical Modeling of Flow Over Two Side Weirs

Nowadays, due to the significant development of hydraulic models, it is possible to investigate miscellaneous hydraulic phenomena and reveal the extent to which their changes in a particular parameter will affect the flow condition without the need of extra experiments. In the present study, flow patterns over a side weir were studied both experimentally and numerically. The experiments were done for a side weir with the length of 4m. However, in the numerical model, the 4m weir was replaced with two side weirs with the length of 2m which were placed within two meters distance from each other. The primary contributions of the paper are to show that a numerical model can be used to simulate the flow over both single and double side weirs, and to quantify the increased discharge from two side weirs relative to discharge from a single side weir having the same crest length as the two side weirs.

Elementary discharge coefficient of a triangular–rectangular sharp-crested side weir in subcritical flow

ABSTRACTSide weirs or lateral weirs are widely employed to divert flows from rivers, channels, sewers and reservoirs or to divide flows between components of water treatment systems. The side weir is a fixed structure installed at one side of a channel for water level control in water treatment plants and irrigation and drainage systems. Hydraulic characteristics of a compound sharp-crested triangular–rectangular side weir under subcritical flow were studied in this paper. The concept of the elementary discharge coefficient that is related to the head to weir height ratio was used to determine the flow through the side weir. The advantage of this method is to calculate the channel water surface profile along the weir. Generalized equations for an elementary discharge coefficient for compound triangular–rectangular side weirs were proposed. Experimental results show the accuracy of the proposed equations.

측면 위어를 넘나드는 천수 흐름에 대한 2차원 수치모의

It was reviewed for the 2D numerical simulations to evaluate the effects of flood control by detention basin, even if stage-discharge relationships for the side weir were not known. A 2D depth-integrated numerical model was constructed by the application of the finite volume method to the shallow water equations as a numerical method and the introduction of an approximate Riemann solver for the accurate calculation of fluxes. Results by the model were compared with those by the laboratory test for the cases of free overflow and submerged flow over a side weir between the channel and storage. The difference between simulated and measured discharge coefficients for the case of free overflow is very small. In addition, the results by simulations were in good agreement with those by experiments for the submerged flow over a side weir and its mechanism was reproduced well. Through this study the discharge coefficients of side weirs can be accurately determined by the 2D numerical model and a considerable degree of accuracy can be achieved to evaluate the effect of flood defenses by detention basins. Thus, it will be expected to apply this model practically to the plan of detention basins, the evaluation of design alternatives, or the management of the existing ones.

Firefly optimization algorithm effect on support vector regression prediction improvement of a modified labyrinth side weir's discharge coefficient

A principal step in designing dividing hydraulic structures entails determining the side weir discharge coefficient. In this study, Firefly optimization-based Support Vector Regression (SVR-FF) is introduced and examined in terms of predicting the discharge coefficient of a modified labyrinth side weir. Ten non-dimensional parameters of various geometrical and hydraulic conditions are defined as the input parameters for the SVR-FF and the side weir discharge coefficient is defined as the output. Improvements in SVR prediction accuracy are determined by comparing SVR-FF with the traditional SVR model. The results indicate that the SVR-FF model with RMSE of 0.035 is about 10% more accurate than SVR with RMSE of 0.039. Thus, combining the Firefly optimization algorithm with SVR increases the prediction model performance.

Flow characteristics of rectangular sharp-crested side weirs in the presence of guide vanes

A side weir is a type of overflow structure that is installed in the side of a channel to evacuate the excessive flow laterally. One of the simple ways to improve the hydraulic performance of this structure is the application of guide vanes. In this study, characteristics of flow over rectangular sharp-crested side weirs in the presence of guide vanes were experimentally investigated. In addition, the behavior of the flow in the absence of vane plates was considered for comparison. Analyzing the measured 3D velocity distribution data indicated that the presence of guide vanes significantly decreased the longitudinal velocity and increased the magnitude of downward velocity over the crest. Furthermore, the presence of guide vanes increased the lateral velocity, thereby resulting in more discharge over the side structure. It also reduced the angle of the spilling jet with the normal to the plane of weir and caused the side weir to work more similarly to a frontal weir.

Influence of the Operating and Geometric Characteristics of a Bottom-hinged Flap Gate on the Discharge Coefficient of a Side Weir

Bottom-hinged flap gates on side weirs are often used for the regulation of flow diversion in case of water abstraction for a variety of needs. In this study, a new equation for the discharge coefficient of a bottom-hinged flap gate on a side weir was proposed on the basis of discharge measurements. The equation was divided into two parts. The first part covers the impact of the sharp-crested side weir and the second the influence of the position and the width of the flap gate. In this manner, the discharge coefficient can be calculated with other authors’ equations for a sharp-crested side weir, which then must be multiplied by the new proposed coefficient. Very good agreement was found between the obtained discharge coefficients and the one calculated with the proposed equation. Furthermore, the results were compared with the equations of other authors for the discharge coefficients of sharp- and broad crested side weirs. The agreement was found to be very good. Additionally, measurements of water levels along the edge of the flap gate and measurements of the velocity field were carried out with a computer-aided visualization method. From these measurements, it was possible to show that the contraction of the water jet varies with the gate-opening angle. It was also found that the side weir with a flap gate has the most favorable hydrodynamic shape around the gate-opening angle of 33°, where the discharge coefficient reaches its maximum.

Adaptive neuro-fuzzy inference system multi-objective optimization using the genetic algorithm/singular value decomposition method for modelling the discharge coefficient in rectangular sharp-crested side weirs

In the present article, the adaptive neuro-fuzzy inference system (ANFIS) is employed to model the discharge coefficient in rectangular sharp-crested side weirs. The genetic algorithm (GA) is used for the optimum selection of membership functions, while the singular value decomposition (SVD) method helps in computing the linear parameters of the ANFIS results section (GA/SVD-ANFIS). The effect of each dimensionless parameter on discharge coefficient prediction is examined in five different models to conduct sensitivity analysis by applying the above-mentioned dimensionless parameters. Two different sets of experimental data are utilized to examine the models and obtain the best model. The study results indicate that the model designed through GA/SVD-ANFIS predicts the discharge coefficient with a good level of accuracy (mean absolute percentage error = 3.362 and root mean square error = 0.027). Moreover, comparing this method with existing equations and the multi-layer perceptron–artificial neural network (MLP-ANN) indicates that the GA/SVD-ANFIS method has superior performance in simulating the discharge coefficient of side weirs.