Discharge coefficient and energy dissipation over stepped spillway under skimming flow regime

Shahheydari, Hossein; Nodoshan, Ehsan Jafari; Barati, Reza; Moghadam, Mehdi Azhdary

doi:10.1007/s12205-013-0749-3

Cited by 57 publications

(20 citation statements)

References 35 publications

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“…5. From this figure may perceive that for the same discharge over spillway, constant height of spillway and different (S) value the increase in (H/ks) value causes a decrease in (ΔE/E0) value, and it was agree with [5], this could be assign to the reason that as the (H/ks) increases the length of step decrease thus decrease the path flow over steps and decreasing the energy dissipation It is also observe that by increasing the amount of discharge over spillways the value of energy dispersion was decrees, this agree with [4,5,14]. In figure it also notices the amount of variation in the reduction of energy dissipation at the same discharge, where energy dissipation is reduced by about 30% when change the slope of spillway from (0.5-1.25) with using 18 steps, and 4% when using (6) steps for spillway.…”

Section: Effect Of (H/ks) To the Energy Dissipation Ratio (δE/e0)supporting

confidence: 69%

“…Described the dissipation of energy for different number of steps showed that reducing the number of steps lead to increased energy dissipation [2,3]. Also numerical studied by using Flow-3D to show the effect of the number of steps and drainage on top of the stepped spillway on the energy dissipation which showed the proof of the inverse relation between the discharge rate and the dissipation of energy and the great software simulation for different cases [4][5][6]. Based on the use of both FLUENT and V-Flow to modeling the unstable twodimensional flow over the stepped spillway, results obtained by the FLUENT program for the energy dissipation for the stepped spillway showed a reasonable agreement in results [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Numerical Simulation for Estimating Energy Dissipation over Different Types of Stepped Spillways and Evaluate the Performance by Artificial Neural Network

Jamel

2018

Tikrit j. eng. sci.

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A B S T R A C TIn this research, Flow-3D software uses to study the energy dissipation for stepped spillways with different end sills. The study is bases on three models. The first model contains rectangular end sills in all steppes. The second model contains rectangular end sills between one step and another. The third model contains triangular end sills in all steppes. For each of these models, three different variables are adopt, slope, height of the spillway and a number of steppes, and four different discharges value, carrying the total number of experiments to (324) tests. Analytical results show that the model (3) is the highest energy dissipation for all discharges value. Empirical equations extraction to find the energy dissipation for each of these models. The artificial neural network is also adopt to prove the accuracy and efficiency of the analytical results which are at high rates of compatibility with the values of the coefficient of determination for (model 1), (model 2) and (model 3) equal to (93.47%), (88.20%) and (86.00%) respectively. Also, artificial neural network identifies the most influential factors on the energy dissipation, the friction Froude number is the highest impact on the energy dissipation for models (1) and (2), while the parameter (b/ks) for the model (1).

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Section: Effect Of (H/ks) To the Energy Dissipation Ratio (δE/e0)supporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Numerical Simulation for Estimating Energy Dissipation over Different Types of Stepped Spillways and Evaluate the Performance by Artificial Neural Network

Jamel

2018

Tikrit j. eng. sci.

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“…Although an unstructured grid needs more time and memory to solve the problem, it is still worth it to use in the study. The unstructured grid for this research was developed in Gambit software by triangular elements [29][30] [31].…”

Section: Geometry and Meshingmentioning

confidence: 99%

Energy Loss Estimation and Flow Simulation in the skimming flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Model

Hamedi¹,

Ketabdar²

2016

IJSEA

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Abstract:Energy dissipaters in dams consider as expensive structures; therefore, economic design of these structure are desirable.Stepped spillways can be use as energy dissipater to reduce the size and cost of the stilling basin. Hard experimental works, high-cost and time-consuming laboratory methods brought about some difficulties to determine the most-efficient design of the steps. This research deals with comparing the two-dimensional numerical simulation and experimental description in stepped spillways equipped with inclined steps and end sill together and presents a quick, trustworthy, economical, and numerical approach to designing the steps. In complicated geometries, simulation is more problematic than simulation of flow in horizontal steps, because it needs more precision around the end sills. Finite volume method and the k-ε standard model are proposed to simulate the flow pattern and evaluate the energy loss over stepped spillway. The flow pattern and velocity vectors resulted from numerical simulation is in a good agreement with the experimental results. Also, energy losses resulted from the numerical approach have been compared with laboratory measurements and demonstrate reasonable agreement.

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“…In addition to these experimental studies, flow on stepped spillways have been modeled numerically with a high degree of accuracy using computational fluid dynamics (CFD). In numerical studies of stepped spillways, the flow over the stepped spillway is investigated by the volume of fluid (VOF) method, with turbulence closures of the k-ε family [26][27][28][29][30][31][32][33][34][35]. For instance, Wan et al [36] have used VOF and the realizable k-ε model to determine the inception point of air entrainment in various stepped spillways, including flat steps, pooled steps, and round steps.…”

Section: Introductionmentioning

confidence: 99%

Stepped Spillways and Energy Dissipation: A Non-Uniform Step Length Approach

Ashoor

Riazi

2019

Applied Sciences

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A stepped spillway, which is defined as a spillway with steps on the chute, can be used to improve the energy dissipation of descending water. Although uniform stepped spillways have been studied comprehensively, non-uniform stepped spillways need more attention. In the interest of maximum energy dissipation, in this study, non-uniform stepped spillways were investigated numerically. To this end, within the range of skimming flow, four different types of non-uniform step lengths, including convex, concave, random, and semi-uniform configurations, were tested in InterFOAM. To evaluate the influence of non-uniform step lengths on energy dissipation, the height and number of steps in all models were fixed and equal to a constant number. The results indicated that in semi-uniform stepped spillways, when the ratio between the lengths of the successive steps is 1:3, a vortex interference region occurs within the two adjacent cavities of the entire stepped chute, and as a result, the energy dissipation increases by up to 20%.

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Discharge coefficient and energy dissipation over stepped spillway under skimming flow regime

Cited by 57 publications

References 35 publications

Numerical Simulation for Estimating Energy Dissipation over Different Types of Stepped Spillways and Evaluate the Performance by Artificial Neural Network

Numerical Simulation for Estimating Energy Dissipation over Different Types of Stepped Spillways and Evaluate the Performance by Artificial Neural Network

Energy Loss Estimation and Flow Simulation in the skimming flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Model

Stepped Spillways and Energy Dissipation: A Non-Uniform Step Length Approach

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