Lateral Intake Research Articles

Numerical Simulation on the Performance Improvement of a Lateral Intake Using Submerged Vanes

Lateral intake is a hydraulic structure which is broadly used for purposes such as agricultural consumption or urban water supply. To improve the efficiency of this structure, it is common to install a submerged vane near the entrance of this structure. Despite common applications of this structure, there is still a lack on correct description of flow structure near this structure and the variability of flow characteristics due to the geometrical characteristics such as lateral intake angle. In present study, we numerically investigate the role of submerged vane and lateral intake angle on flow structure using FLOW-3D simulation package. The results show that the lateral intake with 45° angle has the highest efficiency which can transport the highest amount of water together with lowest amount of sediments to the lateral intake. Moreover, it is also found that formation of a circulation zone between submerged vane and main channel lateral wall causes a high amount water to enter to the lateral intake with the lowest amount of sediment. Finally, simulations of flow in the presence of two submerged vanes show that two submerged vanes installed in a straight line and in a parallel configuration have higher efficiency in conveying water to lateral intake with low amount of sediment.

Investigating Effect of Different Parameters of the Submerged Vanes on the Lateral Intake Discharge Located in the 180 Degree Bend Using the Numerical Model

Intakes are widely used for flow diversion and its control in the open channels or rivers. During passing flow, part of the suspended sediment along with the flow enters the lateral channel and deposits in the lateral intake channel entrance, causing a change in the direction of the flow line towards the shore in front of the reservoir, which reduces the intake efficiency. Submerged vanes are small hydraulic structures that, by creating a secondary flow in their downstream, cause changes in the flow pattern and guide line to the drainage span, and the most important parameters affecting sediment input to the waterfall is the ratio of flow rate. Investigating a laboratory model has high costs and times, which in some cases cannot be justified, therefore, suitable numerical models can be proposed for such options. In this study, using Flow3D, three-dimensional numerical modeling of the flow was calibrated and verified using existing data and numerical modeling accuracy, the relative error of the numerical model was determined. In this study, all effective parameters including submerged vanes type, submerged vanes number, submerged vanes size and Froude number changes in the main channel and type of submerged vanes layout have been investigated. The results of the numerical model show that the angle of inclination of 60 degrees in the entrance intake and the chassis layout in the Froude numbers 0.21-0.33 will result in the most lateral intake discharge.

Simulation of flow pattern at rectangular lateral intake with different dike and submerged vane scenarios

A comprehensive understanding of the sediment behavior at the entrance of diversion channels requires complete knowledge of three-dimensional (3D) flow behavior around such structures. Dikes and submerged vanes are typical structures used to control sediment entrainment in the diversion channel. In this study, a 3D computational fluid dynamic (CFD) code was calibrated with experimental data and used to evaluate flow patterns, the diversion ratio of discharge, the strength of secondary flow, and dimensions of the vortex inside the channel in various dike and submerged vane installation scenarios. Results show that the diversion ratio of discharge in the diversion channel is dependent on the width of the flow separation plate in the main channel. A dike perpendicular to the flow with a narrowing ratio of 0.20 doubles the ratio of diverted discharge in addition to reducing suspended sediment input to the basin, compared with a no-dike situation, by creating the outer arch conditions. A further increase in the narrowing ratio decreases the diverted discharge. In addition, increasing the longitudinal distance between consecutive vanes (Ls) increases the velocity gradient between the vanes and leads to a more severe erosion of the bed, near the vanes.

Investigating the effect of a skimming wall on controlling the sediment entrance at lateral intakes

Sediment entering lateral intakes depends on the flow pattern at the intake entrance. Using a structure in front of the intake entrance can change this pattern and as a result the entering sediment. One of the effective method to change the pattern and manage sediment entering a lateral intake is to use a skimming wall. The removal of sediments from the intake entrance using a skimming wall led to reduction of sediment volume at the intake. To guide flow into the diversion canal and increase skimming wall performance a spur dike was utilized at the opposite side of the intake channel. In this study, the effect of the skimming wall's angle with the bank, a combination of spur dike and skimming wall and discharge changes on controlling sediments entering the intake, intake ratio and bed topography were investigated experimentally. The effect of a skimming wall with three angles (10°, 14°, and 18°) and a combination of skimming wall and spur dike on opposite sides of the intake were investigated. Conducting dimensional analysis, non-dimensional ratios were extracted and test variables were specified. Results showed that in the case of having a skimming wall combined with a spur dike, the amount of sediment entering the intake decreased by 81%, 78.5% and 76% on average for walls with angles of 10°, 14° and 18° respectively. Combining a skimming wall and spur dike has a higher effect on reducing sediments entering the intake compared with a skimming wall alone by about 15%.

Study of the Effect of the Angle of Submerged Vanes on Sediment Control in Lateral Intake at a 180 Degree River Arc

Study of the Effect of the Angle of Submerged Vanes on Sediment Control in Lateral Intake at a 180 Degree River Arc

Optimization of submerged vane parameters

Submerged vanes are airfoils which are in general placed at certain angle with respect to the flow direction in a channel to induce artificial circulations downstream. By virtue of these artificially generated circulations, submerged vanes were utilized to protect banks of rivers against erosion, to control shifting of rivers, to avoid blocking of lateral intake with sediment deposition, etc. Odgaard and his associates have experimentally obtained the optimum vane sizes and recommended that it can be used for vane design. This paper is an attempt to review and validate the findings of Odgaard and his associates by utilizing computational fluid dynamics and experiments as a tool in which the vane generated vorticity in the downstream was maximized in order to obtain optimum vane parameters for single and multiple vane arrays.

Discharge characteristics of lateral circular intakes in open channel flow

Intakes are widely used for flow diversion and its control in the open channels. Circular intakes with bellmouth transitions are used to enhance the discharging capacity of the intakes. Analytical and experimental studies for flow through lateral circular intakes with and without bellmouth in open channels are presented in this paper. This study indicates that the coefficient of discharge for the lateral intake under uniform flow is dependent on the Froude number of the approach flow in the main channel and the ratio of width of the orifice to the width of the main channel. Collected data in this study are used to develop regression equation for the coefficient of discharge. The computed discharges using the proposed equations in this study are within ±10% and ±7% of the observed ones for intake with and without bellmouth, respectively. The discharging capacity of an intake with bellmouth is higher than the intake without transition. Sensitivity analysis indicates that the discharge through bellmouth intake is more sensitive to the low head, as the head increases, the sensitivity for a particular size of intake decreases.

Numerical Simulation of Velocity Distribution in the River Lateral Intake Using the SSIIM2 Numerical Model

Abstract. Intakes are generally used in water distribution networks, irrigation channels, sewage networks, water, and wastewater treatment facilities as an input to power utilities, and so on. Due to the flow complexity and also the Effects of scale, physical models can not solely provide a clear perception of the physics governing the flow field and it is necessary to study this phenomenon numerically along with field and Experimental studies. In the first section of this study, the numerical simulation of flow has been performed in the direct path of rectangular channel by Using SSIIM2 software. This software solves Navier-Stokes equations by Finite-Volume Method (FVM). The flow calculations were performed in the three dimensional model using K-e-RNG and K-e-Standard turbulence models. The K-e-Standard turbulence model showed the best results according to the comparison of velocity profiles with the experimental results of Barkdollet al. (1998) and the results of other numerical studies. Then, in the second section, using this turbulence model, the flow velocity profiles at different sections of the main channel and Intake were compared with the experimental and numerical results of other researchers; and a good agreement has been found between them. The comparison of the obtained results with experimental and numerical results of other researchers indicates that this numerical model can well predict the flow velocity profile in the different sections of the main channel and intake. Given the satisfactory results obtained from the above comparisons, the last section presents a numerical study of other parameters such as shear stress and pressure distribution in the main channel and intake.

Prediction of Scour at a Side-Weir with GEP, ANN and Regression Models

Side-weir is known as a lateral intake structure, which is widely used in irrigation, land drainage, and urban sewerage system by flow diversion device. Local scour in- /volves the removal of material around piers, abutments, side- weir, spurs, and embankments. Clear-water scour depth based on four dimensional parameters: approach flow velocity (V1/Vc), water head ratio (h1 − p)/ h1, side-weir length (L/b) and sediment size (d50/ p). The equilibrium depth of scour increases by the increase of the dimensionless para- meters of approach flow velocity, water head ratio, side-weir length and sediment size. This study presents artificial neural network (ANN) and gene expression programming (GEP) models, which is an algorithm based on genetic algorithms and genetic programming, for prediction of the clear-water scour depth at side-weir. The explicit formulations of the GEP models are developed. The GEP-based formulation and ANN approach are compared with experimental results, mul- tiple linear/nonlinear regressions (MLR/MNLR). The per- formance of GEP is found in slightly more influential than ANN approach and MNLR for predicting the clear-water scour depth at side-weir.

Computer Assisted Preliminary Design of Run-Of-River Plants

Run-of-river type hydroelectric power plants generate electrical energy by using a certain portion of the available flow in the river. A computer program called MINI-HPD is developed to perform the hydraulic design of run-of-river plants. This program, which runs under the Windows operating system, is developed in C# programming language. MINIHPD is capable of performing hydraulic design of structural components of diversion weir with lateral intake and overflow spillway, canal, forebay, and penstock. In addition, it can determine the optimum design discharge, optimum installed capacity, and optimum penstock diameter for this type of plants. It is desired to have quick successive runs under various scenarios and combinations of relevant parameters. An application is presented to illustrate the use of the program

GEP PREDICTION OF SCOUR AROUND A SIDE WEIR IN CURVED CHANNEL

Side-weirs have been widely used in hydraulic and environmental engineering applications. Side-weir is known as a lateral intake structure, which are significant parts of the distribution channel in irrigation, land drainage, and urban sewerage system, by flow diversion device. Local scour involves the removal of material around piers, abutments, side-weir, spurs, and embankments. Clearwater scour depth based on five dimensional parameters: approach flow velocity (V1/Vc), water head ratio (h1–p)/h1, side-weir length (L/r), side-weir crest height (b/p) and angle of bend θ. The aim of this study is to develop a new formulation for prediction of clear-water scour of side-weir intersection along curved channel using Gene Expression Programming (GEP) which is an algorithm based on genetic algorithms (GA) and genetic programming (GP). In addition, the explicit formulations of the developed GEP models are presented. Also equations are obtained using multiple linear regressions (MLR) and multiple nonlinear regressions (MNRL). The performance of GEP is found more influential than multiple linear regression equation for predicting the clearwater scour depth at side-weir intersection along curved channel. Multiple nonlinear regression equation was quite close to GEP, which serve much simpler model with explicit formulation.

The Effect of Submerged-Vanes on Formation Location of the Saddle Point in Lateral Intake from a Straight Channel

One of the most important problems that the river engineers have long been faced with lateral intake from rivers is sedimentation in intakes. Formation of the saddle point nearby the intake entrance is one of the main reasons for entry of the sediments into the intake channel. Using the structures in the rivers causes change of the flow pattern and consequently changing of the formation location of the saddle point. The submerged vanes are one of the structures that are installed with different dimensions and configuration in front of the intake channel to control the sediment issues,. In this study the impact of the submerged vanes dimensions and configuration on the formation location of saddle point has been investigated. The FLUENT mathematical model has been used for the simulation. Various range of the parameters has been considered for them based on the recommended range, and the simulations have been performed in three intake ratios of 0.11, 0.16 and 0.21. The results showed that increasing the vanes height has a positive effect on intake conditions, and results in formation of the saddle point in a distance farther from the intake entrance and omission of the return flows. Utilization of submerged vanes with larger transverse distance is better for intake from rivers as no flow from downstream side of the intake channel returns to it. As the intake ratio increases the saddle point forms at a distance closer to the intake entrance, and the return flows are entered into the intake from the downstream corner of the intake entrance. Formation location of the saddle point is independent from other parameters.

Experimental effect of flow depth on ratio discharge in lateral intakes in river bend

Open-channel dividing flow is characterized by the inflow and outflow discharges, the upstream and downstream water depths, and the recirculation flow in the branch channel. In general, diversion flow can be categorized as natural and artificial flow. Natural flow diversion usually occurs as braiding or cut-off in bend rivers, while artificial flow is man-made to divert flow by lateral intake channels for water supply. This study presents the results of a laboratory research into effect intake flow depth on ratio discharge in lateral intakes in 180 degree bend. Investigation on lateral intake and determination of intake flow depth is among the most important issues in lateral intake on ratio discharge with model intake flow depth were measured in a laboratory flume under clear-water. Experiments were conducted for various intake flow depths and with different discharges. It was found that by increasing the flow depth at 180 degree flume bend, ratio discharge increases.

SCOUR IN FRONT OF THE LATERAL INTAKES DUE TO USING SINGLE ROW OF SUBMERGED VANES

Submerged vanes can be used to create sufficient depth for navigation, to mitigate bank erosion or to divert sediment away of lateral intakes. Besides these intended effects, submerged vanes also produce local scour, which may interfere with the intended morphological correction and which is relevant to the structural stability of the vanes. The present paper shows an experimental study that was executed in order to investigate the local scour that induced in front of the lateral intakes due to using a single row of submerged vanes to minimize the sediment that entered the intake channel. Sixty experiments were carried out using a single row of vanes, considering various vane heights, angles, and positions under different flow conditions. A case of flat floor without vanes was included to estimate the influence of the submerged vanes on the scour in front of the diversions. Obtained results were analyzed and graphically presented, and also provide simple formulas to compute the maximum scour depth in vicinity of the single submerged vanes at different flows entering the lateral intake.

Study of flow structure and sediment entry to a lateral intake

This paper reports on a set of laboratory experiments involving a layout that is common in irrigation diversion works. The layout involves a lateral intake channel with a diversion dam, positioned to allow the flow to be controlled and managed. Based on experimental measurements and observations, the effect of diversion angle (ranging from 90 to 120°) on the structure of the approaching flow to the lateral intake and amount of sediment entering the intake was investigated. Velocity fields both upstream of the intake in the main channel and in front of the intake in the sluiceway were measured under various discharge combinations of the river, intake and sluice gate. Analysis of sediment measurements showed that the intake with a diversion angle of 110° had the least amount of sediment entering the intake. Analysis of the streamlines in the main channel showed that the width of the bottom-diverted current in the main channel decreased as the diversion angle increased. Furthermore, analysis of the data showed that the product of the width of the diverted current and the mean shear stress decreased when the diversion angle increased from 90 to 110° before increasing again at 120°.

Investigation of flow at a right-angled lateral intake

Based on experimental measurements and observations in a laboratory channel, the hydrodynamic behaviour of the approaching flow and the amount of sediment entering a right-angled lateral intake in a diversion dam were investigated. The velocity field, both upstream of the intake in the main channel and in front of the intake in the sluiceway, were measured under various discharge combinations of the river, intake and sluice gate. In addition, velocity profiles both upstream and downstream of the intake and the amount of sediment entering it were measured. Analysis of the velocity data showed that the discharge of the sluice gate played an important role in determining the velocity profile and also the mechanism of sediment entry. All velocity profiles where the sluice gate was closed had an inflection point, where the flow direction changed, leading to a return velocity near the bed. The elevation of this point was a function of the intake discharge and approximately equal to the height of the entrance sill. Experimental observation showed that sediment entered the intake by a tornado-like vortex. The strength and frequency of the vortices depended on the intake and sluice gate discharges. Analysis of the sedimentation data showed that the amount of sediment entering the intake increased with increasing intake discharge. In addition, an increase in the sluice gate discharge caused an increase of sediment entry to the intake under the same intake discharge.

Persistent hunger for sodium makes brain stimulation not so sweet: Theoretical comment on Morris et al. (2006).

The rewarding value of a stimulus is not fixed but rather is subjective and can vary with motivational state. M. J. Morris, E. S. Na, A. J. Grippo, and A. K. Johnson (2006) report that generating a prolonged sodium appetite decreases the rewarding value of lateral hypothalamic brain stimulation and sucrose intake. The findings support the idea that a specific motivational state can have strong, nonspecific consequences for reward processing.

Two-dimensional model for lateral intake flows

This paper gives details of the refinement and application of a two-dimensional horizontal model for rivers. An explicit finite-difference algorithm was used for solving the governing differential equations, which includes the conservation of mass and momentum to predict hydrodynamic parameters. The model includes different turbulence closure models—that is, constant eddy viscosity, Prandtl simple mixing length and Smagorinsky methods. An experimental programme was designed and carried out in a laboratory flume to measure the length of eddy produced at the entrance of the intake. Model predictions have been compared with experimental results for a lateral intake. The effect of different hydrodynamic parameters on the results obtained from several turbulence models has also been investigated. Turbulence model parameters have been calibrated according to experimental measurements. Finally, results have been classified for application of different turbulence models in lateral intakes.

Side-Weir Flow in Curved Channels

Side-weirs located on straight channels have attracted considerable interest and research effort. The same, however, is not true for side-weirs on curved channels. The existing studies deal mainly with sediment transport problems and lateral intake structures. The present study focuses on the investigation of the hydraulic behavior of a rectangular sharp crested weir at various locations along a 180° bend. The flow resulting from the effects of the bend and the side-weir was investigated experimentally. Velocity measurements were carried out both for the bend with and without active overflow conditions while surface profiles were determined only for the former case. Velocity measurements were made over the depth at several cross sections along the bend. Observations indicated that a stagnation zone existed at the side-weir section along the inner side of the bend, and that standing waves were present downstream of the side-weir even under subcritical flow conditions. Both phenomena were found to be highly dependent on the upstream Froude number. The side-weir discharge coefficient was determined at one section along the approach to the bend and at five stations along the bend for a number of different side-weir dimensions. The side-weir discharge coefficient along the bend was found to depend on the upstream Froude number, the dimensionless weir height, p/h1, and the dimensionless weir length, L/b. The variation of the discharge coefficient along the bend as a function of the Froude number and the dimensionless weir length was found to exhibit a parabolic relationship.