scholarly journals Energy dissipation performance of the trapezoidal stepped spillway

2021 ◽  
Author(s):  
Erdinc Ikinciogullari ◽  
Keyword(s):  
Energy Dissipation ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
Stepped Spillway ◽  
Base Length ◽  
Stepped Spillways

Stepped spillways are a more effective type of spillway in energy dissipation than conventional chute channels. Therefore, the dimensions of the energy breaker at the downstream of the stepped spillways are lower. It is an alternative especially for the downstream pool that cannot be built in sufficient length due to the terrain conditions. In this study, the energy dissipation performance of the trapezoidal stepped spillways was investigated numerically by using Flow3D software. Four different models and three different discharges were utilized for this aim. According to the results, the trapezoidal stepped spillway is more effective up to 30% than classical stepped spillways in energy dissipation. The depth of the trapezoidal step and the bottom base length of the trapezoid significantly affected the energy dissipation rate for the trapezoidal stepped spillway.

scholarly journals Energy Dissipation in Stepped Spillways with Different Horizontal Face Angles

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4469
Author(s):  
Peng ◽  
Zhang ◽  
Yuan ◽  
Li ◽  
Xie ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Dissipation Rate ◽  
Free Water ◽  
Energy Dissipation Rate ◽  
Field Energy ◽  
Stepped Spillway ◽  
Turbulent Model ◽  
Relevant Research ◽  
Unit Discharge ◽  
Stepped Spillways

Energy dissipation is one of the most important factors in choosing stepped spillways. However, very few studies have investigated energy dissipation with different horizontal face angles. In this paper, the realizable k-ε turbulent model was used to study the flow field, energy dissipation rates and turbulent kinetic energy and its dissipation rate for different stepped spillways with five horizontal face angles in the skimming flow regions. Results showed that the field and direction of the flow were changed by the horizontal face angles of the stepped spillway, which produced some unique characteristics and thus caused better energy dissipation. The fluctuation of free water surface will be larger with increasing horizontal face angles and the energy dissipation rate decreases with an increasing unit discharge and increases for the enlargement of the horizontal face angles. This conclusion could provide a reference for the relevant research of V shaped stepped spillways.

scholarly journals Numerical Investigation on the Hydraulic Properties of the Skimming Flow over Pooled Stepped Spillway

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1478 ◽  
Author(s):  
Shicheng Li ◽  
Jianmin Zhang
Keyword(s):  
Energy Dissipation ◽  
Transverse Direction ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Energy Dissipation Rate ◽  
Spanwise Direction ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Aeration Efficiency ◽  
Horizontal Step

Pooled stepped spillway is known for high aeration efficiency and energy dissipation, but the understanding for the effects of pool weir configuration on the flow properties and energy loss is relatively limited, so RNG k − ε εturbulence model with VOF method was employed to simulate the hydraulic characteristics of the stepped spillways with four types of pool weirs. The calculated results suggested the flow in the stepped spillway with staggered configuration of` two-sided pooled and central pooled steps (TP-CP) was highly three dimensional and created more flow instabilities and vortex structures, leading to 1.5 times higher energy dissipation rate than the fully pooled configuration (FP-FP). In FP-FP configuration, the stepped spillway with fully pooled and two-sided pooled steps (FP-TP) and the spillway with fully pooled and central pooled steps (FP-CP), the pressure on the horizontal step surfaces presented U-shaped variation, and TP-CP showed the greatest pressure fluctuation. For FP-TP and FP-CP, the vortex development in the transverse direction presented the opposite phenomenon, and the maximum vortex intensity in TP-CP occurred at Z/W = 0.25, while FP-FP illustrated no significant change in the transverse direction. The overlaying flow velocity distribution in the spanwise direction demonstrated no obvious difference among FP-FP, FP-TP, and FP-CP, while the velocity in TP-CP increased from the axial plane to the sidewalls, but the maximum velocity for all cases were approximately the same.

scholarly journals Numerical Simulation of Stepped Spillways with Front Step Deformation

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guodong Li ◽  
Haifeng Zhang ◽  
Xingnan Li ◽  
Lihao Guo ◽  
Yanyan Gao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Energy Dissipation ◽  
Water Flow ◽  
Dissipation Rate ◽  
Energy Dissipation Rate ◽  
Maximum Energy ◽  
Single Step ◽  
Stepped Spillway ◽  
Flow State ◽  
Front Step

In order to solve the flood discharge problem of both small- and medium-sized warping dams in the Loess Plateau, a stepped spillway scheme, based on an ecological bag, to achieve full-section water flow and energy dissipation has been proposed in this paper. The hydraulic and energy dissipation characteristics of a stepped spillway layout scheme were studied using 3D numerical simulation. As the height of the dams is low and the spillways are short, the research has shown that the traditional single-step layout scheme leads to a low overall energy dissipation rate due to the small amount of energy dissipated in the initial steps. As a result of this, this paper has put forward two kinds of step layout schemes such as the shunt type and the staggered type for the initial steps. Through analysis of the flow state, the pressure distribution, and the total energy dissipation rate, the results have shown that shunt type and staggered type with front step deformation produced an obvious mixing of the water flow, fewer negative pressure areas, and a higher energy dissipation rate. The optimal energy dissipation rate of the staggered type reached 87.75%, and the maximum energy dissipation rate was increased by 27.97%.

scholarly journals Analysis of Energy Dissipation of Interval-Pooled Stepped Spillways

Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 85
Author(s):  
Xin Ma ◽  
Jianmin Zhang ◽  
Yaan Hu
Keyword(s):  
Renormalization Group ◽  
Energy Dissipation ◽  
Turbulence Model ◽  
Dissipation Rate ◽  
Flow Characteristics ◽  
Stepped Spillway ◽  
Flat Panel ◽  
Stepped Spillways ◽  
Capture Technique ◽  
Better Than

The water flow characteristics over an interval-pooled stepped spillway are investigated by combining the renormalization group (RNG) k-ε turbulence model with the volume of fluid (VOF) interface capture technique in the present study. The results show that the energy dissipation performance of the interval-pooled stepped spillway was generally better than that of the pooled, stepped spillways and the traditional flat-panel stepped spillway. The omega vortex intensity identification method is introduced to evaluate the energy dissipation. Due to the formation of “pseudo-weir”, the energy dissipation did not increase with the growth of the pool’s height. In addition, the average vortex intensity can characterize the dissipation rate to some extent.

scholarly journals A Study of the Conditions of Energy Dissipation in Stepped Spillways with Λ-shaped step Using FLOW-3D

2017 ◽  
Vol 3 (10) ◽  
pp. 856 ◽  
Author(s):  
Abbas Mansoori ◽  
Shadi Erfanian ◽  
Farhad Khamchin Moghadam
Keyword(s):  
Energy Dissipation ◽  
Dissipation Rate ◽  
Mesh Networks ◽  
Maximum Flow ◽  
Energy Dissipation Rate ◽  
Maximum Energy ◽  
Trial And Error ◽  
Stepped Spillways ◽  
Flow Energy ◽  
Proposed Model

In the present study, energy dissipation was investigated in a specific type of stepped spillways. The purpose was to achieve the highest level of energy dissipation in downstream of the spillway. It was performed by providing a specific type of geometry for step as a great roughness. Here, steps were recognized as great roughness against flow. Their shape and number were designed in such a way that the maximum flow energy can be minimized in this stage, i.e. over steps before reaching to downstream. Accordingly, it can be stated that the highest energy dissipation rate will be obtained in the structure at downstream. Moreover, thereby, heavy costs imposed by designing and constructing stilling basin on project can be minimized. In this study, FLOW-3D was employed to analyse and obtain energy dissipation rate. The best geometry of the steps, through which the maximum energy dissipation can be achieved, was determined by reviewing related literature and inventing the proposed model in FLOW-3D. To evaluate the proposed method, analyses were performed using trial and error in mesh networks sizes as well as the mentioned methods and the results were compared to other studies. In other words, the most optimal state was obtained with Λ-shaped step at angel of 25 degree with respect to energy dissipation rate compare to smooth step.

scholarly journals Numerical study of energy dissipation and block barriers in stepped spillways

2020 ◽  
Author(s):  
Mehdi Karami Moghadam ◽  
Ata Amini ◽  
Ehsan Karami Moghadam
Keyword(s):  
Energy Dissipation ◽  
Numerical Study ◽  
Flow Simulation ◽  
Step Length ◽  
Energy Dissipation Rate ◽  
Relative Energy ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Using Data ◽  
Turbulent Models

Abstract In this research, the accuracy of the Flow-3D numerical model in the flow simulation in a stepped spillway was probed using data obtained from the physical model. In addition, the effects of block barriers on the energy dissipation rate were investigated. To adopt a proper turbulent model, Renormalization Group k-ε, RNG k-ε, and standard k-ε models were employed. Then, the Flow-3D was run in five discharges for nine spillways with the ratios of block length to step length (Lb/l) and block height to step height (Hb/h) as 0.3, 0.4, and 0.5. The results indicated that both turbulent models had almost similar outcomes though the run time of the RNG k-ε model was shorter. The blocks with a shorter length in low ratios of Hb/h and the lengthier blocks in high ratios of Hb/h undergo more relative energy dissipation relative to the no-block situation. For Hb/h = 0.3 and Lb/l equal to 0.3, 0.4, and 0.5, the relative energy dissipation climbed on average as 8.5, 6.5, and 4.5% respectively, compared with the no-block case. The most influence exerted on relative energy dissipation was obtained via the blocks with Hb/h = Lb/l equal to 0.3 and 0.5 with respective increases of 8.6 and 8.4%.

scholarly journals Multi-objective optimization of stepped spillway and stilling basin dimensions

2021 ◽  
Author(s):  
Fatiha Lebdiri ◽  
Abdelghani Seghir ◽  
Ali Berreksi
Keyword(s):  
Decision Making ◽  
Energy Dissipation ◽  
Dissipation Rate ◽  
Clustering Algorithm ◽  
Optimization Procedure ◽  
Energy Dissipation Rate ◽  
Stepped Spillway ◽  
Multi Objective Optimization ◽  
Stilling Basin ◽  
Multi Objective

Abstract In the present paper, an optimization procedure is proposed for stepped spillway design dimensions, which leads to maximum energy dissipation rate and minimum construction cost considering independently the chute cost and stilling basin cost. Three independent objective functions are thus simultaneously satisfied. The procedure involves four main tools: The multi-objective particle swarm optimization method (MOPSO) to find Pareto solutions in one run, the K-means clustering algorithm to reduce the size of the obtained non-dominated solutions, the pseudo-weight vector approach (PWV) to facilitate the decision making and to select some adequate solutions, and finally, CFD simulations to analyze the retained optimal solutions. The suitability of the proposed procedure is tested through an example of application. As results, a set of twenty solutions with different satisfaction levels are found and compared to existing solutions. A multi-objective optimization problem may have many different solutions, the originality of the present work lies in the proposed procedure which explores several possible ones and reduces their number to give help for the decision making. Furthermore, an approximate expression of spillway total cost is also derived as a function of flow energy dissipation rate.

scholarly journals Numerical Study to Evaluate the Performance of Nonuniform Stepped Spillway Using ANSYS-CFX

2020 ◽  
Vol 10 (2) ◽  
pp. 1-9
Author(s):  
Shawnm M. Saleh ◽  
Sarhang M. Husain
Keyword(s):  
Energy Dissipation ◽  
Numerical Study ◽  
Energy Dissipation Rate ◽  
Step Height ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Flow Discharge ◽  
Flow Energy ◽  
Ansys Cfx ◽  
Inception Point

The main features that attract hydraulic engineers for designing stepped spillways are their ability to lose a large portion of the flow energy and add or increase aeration to the flow naturally. Hence, smaller size stilling basin and no aeration device may require. This study aims to find the amount of energy dissipation rate and the location of inception point over non-uniform stepped spillway. The numerical 2D ANSYS-CFX code is applied to generate and run thirty-two models of different configurations using two different moderate slopes (1 V:2 H and 1 V:2.5 H) as most of the downstream slopes designed for moderate slope, and two different step heights (hs= 0.08 m and hs= 0.016 m) under skimming flow discharge for different (dc/hs) ranging from dc/hs= 1–2.2, in which dc is the critical flow deptho n the crest. The volume of fluid is implemented and the renormalized group of k-ɛ turbulence model is activated. The computational results demonstrated that the amount of energy dissipation increases with decreasing the flow discharge, chute slope, and step height. In addition, it is observed that the length of the inception point is directly proportional to the discharge and inversely proportional to both the chute slopes and step height. Moreover, for the design point of view, the results revealed that configuration B can be considered as the optimal one amongst the others examined herein.

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