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 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 Stepped spillway flows and air entrainment

1993 ◽  
Vol 20 (3) ◽  
pp. 422-435 ◽  
Author(s):  
Hubert Chanson
Keyword(s):  
Energy Dissipation ◽  
Flow Characteristics ◽  
Air Entrainment ◽  
Stepped Spillway ◽  
Calculation Methods ◽  
Stepped Spillways ◽  
Popular Method ◽  
Roller Compacted Concrete ◽  
Construction Techniques ◽  
Recent Developments

Stepped spillways have become a popular method for handling flood releases. The steps significantly increase the rate of energy dissipation taking place on the spillway face and reduce the size of the required downstream energy dissipation basin. The compatibility of stepped spillways with roller compacted concrete and gabion construction techniques results in low additional cost for the spillway. This paper presents a review of recent developments for the design of stepped spillways, provides a discussion of the effects of air entrainment, and presents new calculation methods that take into account the effects of flow aeration on the flow characteristics and the rate of energy dissipation. Key words: stepped spillway, air entrainment, dam, spillway, energy dissipation.

scholarly journals Analysis of Flow Characteristics and Effects of Turbulence Models for the Butterfly Valve

2021 ◽  
Vol 11 (14) ◽  
pp. 6319
Author(s):  
Sung-Woong Choi ◽  
Hyoung-Seock Seo ◽  
Han-Sang Kim
Keyword(s):  
Turbulence Model ◽  
Dissipation Rate ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Flow Properties ◽  
Nominal Diameter ◽  
Large Pressure ◽  
Sst Model ◽  
Turbulence Effect ◽  
Valve Opening

In the present study, the flow characteristics of butterfly valves with different sizes DN 80 (nominal diameter: 76.2 mm), DN 262 (nominal diameter: 254 mm), DN 400 (nominal diameter: 406 mm) were numerically investigated under different valve opening percentages. Representative two-equation turbulence models of two-equation k-epsilon model of Launder and Sharma, two-equation k-omega model of Wilcox, and two-equation k-omega SST model of Menter were selected. Flow characteristics of butterfly valves were examined to determine turbulence model effects. It was determined that increasing turbulence effect could cause many discrepancies between turbulence models, especially in areas with large pressure drop and velocity increase. In addition, sensitivity analysis of flow properties was conducted to determine the effect of constants used in each turbulence model. It was observed that the most sensitive flow properties were turbulence dissipation rate (Epsilon) for the k-epsilon turbulence model and turbulence specific dissipation rate (Omega) for the k-omega turbulence model.

scholarly journals Uniform flow and energy dissipation of hydraulic-jump-stepped spillways

2020 ◽  
Vol 20 (4) ◽  
pp. 1546-1553
Author(s):  
Yu Zhou ◽  
Jianhua Wu ◽  
Fei Ma ◽  
Jianyong Hu
Keyword(s):  
Energy Dissipation ◽  
Water Flow ◽  
Hydraulic Jump ◽  
Flow Region ◽  
Uniform Flow ◽  
Stepped Spillway ◽  
Flow Depth ◽  
Clear Water ◽  
Air Concentration ◽  
Stepped Spillways

Abstract In skimming flow, a uniform flow can be achieved and the flow depth, velocity and air concentration remain constant if a stepped spillway is sufficiently long. In this study, physical model experiments were performed to investigate the uniform characteristics and energy dissipation of a hydraulic-jump-stepped spillway, which is a new type of stepped spillway for increasing the unit discharge capacity and energy dissipation. Based on the redefinition of uniform flow, experimental results show that at a given stepped spillway slope, a smaller height for the beginning of the uniform flow region, a greater uniform aerated flow depth and a greater uniform equivalent clear water flow depth can be obtained as compared with the traditional stepped spillway due to strong aeration in the aeration basin. Under the condition of uniform flow, the energy dissipation rate of stepped spillways can be estimated by the equivalent clear water flow depth with given inflow conditions. Compared with the traditional stepped spillway, the uniform flow over the hydraulic-jump-stepped spillway has a smaller specific energy, revealing that the hydraulic-jump-stepped spillway is more advantageous for dissipating energy, especially at large unit discharges.

scholarly journals Numerical investigation of flow characteristics over stepped spillways

2020 ◽  
Author(s):  
Aytaç Güven ◽  
Ahmed Hussein Mahmood
Keyword(s):  
Numerical Model ◽  
Turbulent Flow ◽  
Flow Characteristics ◽  
Air Entrainment ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Entrainment Velocity ◽  
Fluid Flow Characteristics ◽  
3D Package ◽  
Good Agreement

Abstract Spillways are constructed to evacuate the flood discharge safely not to let the flood wave overtop the dam body. There are different types of spillways, ogee type being the conventional one. Stepped spillway is an example of nonconventional spillways. The turbulent flow over stepped spillway was studied numerically by using the Flow-3D package. Different fluid flow characteristics such as longitudinal flow velocity, temperature distribution, density and chemical concentration can be well simulated by Flow-3D. In this study, the influence of slope changes on flow characteristics such as air entrainment, velocity distribution and dynamic pressures distribution over the stepped spillway was modelled by Flow-3D. The results from the numerical model were compared with the experimental study done by others in the literature. Two models of the stepped spillway with different discharge for each model was simulated. The turbulent flow in the experimental model was simulated by the Renormalized Group (RNG) turbulence scheme in the numerical model. A good agreement was achieved between the numerical results and the observed ones, which were exhibited in terms of graphics and statistical tables.

scholarly journals Genetic algorithms for optimizing stepped spillways to maximize energy dissipation

2021 ◽  
Author(s):  
Farzin Salmasi ◽  
John Abraham
Keyword(s):  
Water Management ◽  
Genetic Algorithm ◽  
Energy Dissipation ◽  
Objective Function ◽  
Relative Energy ◽  
Stepped Spillway ◽  
Construction Time ◽  
Stepped Spillways ◽  
Decision Variables ◽  
West Azerbaijan

Abstract Stepped spillways are important water-management structures that are used for energy dissipation. Use of these spillways has increased in recent decades, they can reduce construction time and they are effective for reducing the flow's downstream kinetic energy. In this study, the width and height of the steps as well as the slope and height of the overflow spillway were considered as variables. Due to the large number of variables, non-linearity of the objective function and constraints, and the lack of an explicit relationship between decision variables, a genetic algorithm (GA) was used. A stepped spillway with optimal dimensions was proposed as a replacement of the smooth spillway of Sarogh Dam located in West Azerbaijan province, Iran. The proposed steps increase energy dissipation; for constant discharge and varying slopes, the changes in the optimal height of the steps were insignificant. Sensitivity analysis using the objective function showed that the relative energy dissipation for a constant discharge is independent of the optimal height of the steps and decreases with increasing spillway slope. In addition, for fixed slopes, increasing the flow rate leads to a decrease in relative energy dissipation and an increase in the optimal height of the steps.

scholarly journals Influence of aeration induced by piers on the starting position of the flow aeration and extreme pressures in stepped spillways

RBRH ◽  
2021 ◽  
Vol 26 ◽  
Author(s):  
Priscila dos Santos Priebe ◽  
Rute Ferla ◽  
Carolina Kuhn Novakoski ◽  
Aline Saupe Abreu ◽  
Eder Daniel Teixeira ◽  
...  
Keyword(s):  
Physical Model ◽  
Experimental Analysis ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Exceedance Probability ◽  
Stepped Spillway ◽  
Air Concentration ◽  
Stepped Spillways ◽  
Starting Position ◽  
Cavitation Phenomenon

ABSTRACT The operation of stepped spillways is limited by a range of discharges due to the risk of occurrence of the cavitation phenomenon and erosion on its steps. Since there is a demand for spillways with the possibility of overflow of greater discharges, the designs seek to increase the air concentration of the flow, which can occur through the installation of piers in the spillway in order to protect the structure from the above mentioned damage. The aim of this work is to analyze flow characteristics and extreme minimum and maximum pressures with non-exceedance probability of 0.1% and 99.9% acting next to the step edges of the spillway with aeration induced by piers through an experimental analysis in a physical model. Based on the results obtained, flow behavior was defined and equations for predicting the extreme pressures that occur along the stepped spillway with aeration induced by piers were proposed.

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

2019 ◽  
Vol 9 (23) ◽  
pp. 5071
Author(s):  
Abdelwanees Ashoor ◽  
Amin Riazi
Keyword(s):  
Energy Dissipation ◽  
Step Length ◽  
Maximum Energy ◽  
Stepped Spillway ◽  
Constant Number ◽  
Stepped Spillways ◽  
Interference Region ◽  
Different Types ◽  
Stepped Chute

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%.

Sign in / Sign up

Export Citation Format

Share Document