Simple Design Criterion for Residual Energy on Embankment Dam Stepped Spillways

Felder, Stefan; Chanson, Hubert

doi:10.1061/(asce)hy.1943-7900.0001107

Cited by 34 publications

(24 citation statements)

References 26 publications

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“…Friction factors of the unvegetated chute (NV) were in good agreement with the results of Severi () for smooth spillways. For stepped chutes, 0.1 ≤ f e ≤ 0.4 was found for typical embankment slopes (Felder & Chanson, ). Friction factors of the vegetated chutes were similar or above the stepped spillway data.…”

Section: Energy Dissipation and Flow Resistancementioning

confidence: 87%

“…These and many further studies used phase-detection intrusive probes to measure the air-water flow properties and to estimate the design parameters including flow resistance and energy dissipation performance. Typical equivalent Darcy-Weisbach friction factors for such aerated flows are 0.008 ≤ f e ≤ 0.061 for very smooth chutes (Severi, 2018), 0.1 ≤ f e ≤ 0.4 for stepped spillways (Felder & Chanson, 2015c), and 0.41 ≤ f e ≤ 4.59 for rock chutes (Pagliara et al, 2010). The commonly applied air-water flow measurement and data processing methods can be directly applied to vegetated chutes.…”

Section: Introductionmentioning

confidence: 99%

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Flow Resistance and Energy Dissipation in Supercritical Air‐Water Flows Down Vegetated Chutes

Scheres

Schüttrumpf

Felder

2020

Water Resources Research

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Vegetation covers on dikes and embankment dams have proven as sustainable and cost‐effective surface protection against external erosion caused by hydraulic, mechanical, or climatic impacts. Determination of the hydraulic loads that act upon these covers requires the knowledge of the flow resistance. While the high‐velocity flows on vegetated slopes are often aerated, the flow aeration has rarely been considered, and no direct measurements of the air‐water flow properties have been conducted to date. The air‐water flow properties are needed for a direct estimation of important design parameters such as friction factors and residual head at the downstream end. Herein, unique air‐water flow measurements were conducted in high‐velocity air‐water flows down a vegetated chute with a 1:3 slope. Several vegetation covers were tested for a range of flow rates. The experiments revealed strong flow aeration within three‐dimensional, fragmented flows associated with complex interactions of vegetation and high‐velocity flows. The air‐water flow properties were measured with phase‐detection intrusive probes providing novel insights into aerated flows on vegetated chutes including distributions of void fraction, bubble count rate, and interfacial velocity as well as direct estimates of energy dissipation and flow resistance. The results highlighted strong flow aeration and energy dissipation for all vegetated configurations. The median equivalent Darcy‐Weisbach friction factors for all vegetations were within 0.19 to 0.45, comparable to aerated flows on stepped spillways. The present results highlighted the significant flow resistance of vegetated covers and the need to consider air‐water flow properties in the design of vegetated chutes.

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Section: Energy Dissipation and Flow Resistancementioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Flow Resistance and Energy Dissipation in Supercritical Air‐Water Flows Down Vegetated Chutes

Scheres

Schüttrumpf

Felder

2020

Water Resources Research

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“…A large number of experimental studies have been conducted in the past decades uncovering key features of the air-water flows and providing design guidelines for smooth and stepped spillways (e.g. STRAUB and ANDERSON 1958;MATOS 2000;BOES and HAGER 2002;GONZALES and CHANSON 2007;FELDER and CHANSON 2016a). These studies relied on suitable air-water flow instrumentation because classical instrumentation such as Pitot tube, PIV, LDV and ADV cannot produce reliable results when the local void fraction exceeds some 5% (CHANSON 2013).…”

Section: Introductionmentioning

confidence: 99%

Comparative analyses of phase-detective intrusive probes in high-velocity air–water flows

Felder

Pfister

2017

International Journal of Multiphase Flow

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A comparative analysis of a wide range of air-water flow properties was conducted for two types of phase-detection intrusive probes including fiber-optical and conductivity probes. Experiments were conducted on a stepped spillway model for a skimming flow discharge q = 0.478 m 2 /s and for Re = 4.7 10 5 in a flow region just downstream of the inception point of free-surface aeration and in the fully developed flow region. The comparison of a large number of key air-water flow properties showed a very close agreement for the two sensor types including void fraction, interfacial velocity and equivalent clear water flow depth enabling a direct comparison of past and future data collected with either phase-detection probe type. Minor differences were observed in terms of chord sizes, clustered properties and interparticle arrival times linked with the slightly smaller sensor size of the fiber-optical probe. The in-line positioning of the leading and trailing tips of the fiber-optical probe affected the trailing tip properties resulting in elevated turbulence intensities. An optimum dual-tip phase-detection probe design should consist of small probe tips positioned side-by-side.

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“…Severe erosions at the downstream channel may harm the stability of the hydraulic structures as documented by Dodaro et al [43,44]. More practical issues on the stepped spillway design and energy dissipation have been thoroughly studied in the benchmark of [45][46][47]. Therefore, a thorough understanding of the energy dissipation features can help to better evaluate the design of stepped spillways and other energy dissipaters such as the tailing basin.…”

Section: Analysis Of Energy Dissipation Efficiency Of Spillway With Dmentioning

confidence: 99%

SPHysics Simulation of Experimental Spillway Hydraulics

Ren

Wang

et al. 2017

Water

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Abstract:In this paper, we use the parallel open source code parallelSPHysics based on the weakly compressible Smoothed Particle Hydrodynamics (WCSPH) approach to study a spillway flow over stepped stairs. SPH is a robust mesh-free particle modelling technique and has great potential in treating the free surfaces in spillway hydraulics. A laboratory experiment is carried out for the different flow discharges and spillway step geometries. The physical model is constructed from a prototype reservoir dam in the practical field. During the experiment, flow discharge over the weir crest, free surface, velocity and pressure profiles along the spillway are measured. In the present SPH study, a straightforward push-paddle model is used to generate the steady inflow discharge in front of the weir. The parallelSPHysics model is first validated by a documented benchmark case of skimming flow over a stepped spillway. Subsequently, it is used to reproduce a laboratory experiment based on a prototype hydraulic dam project located in Qinghai Province, China. The detailed comparisons are made on the pressure profiles on the steps between the SPH results and experimental data. The energy dissipation features of the flows under different flow conditions are also discussed. It is shown that the pressure on the horizontal face of the steps demonstrates an S-shape, while on the vertical face it is negative on the upper part and positive on the lower part. The energy dissipation efficiency of the spillway could reach nearly 80%.

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Simple Design Criterion for Residual Energy on Embankment Dam Stepped Spillways

Cited by 34 publications

References 26 publications

Flow Resistance and Energy Dissipation in Supercritical Air‐Water Flows Down Vegetated Chutes

Flow Resistance and Energy Dissipation in Supercritical Air‐Water Flows Down Vegetated Chutes

Comparative analyses of phase-detective intrusive probes in high-velocity air–water flows

SPHysics Simulation of Experimental Spillway Hydraulics

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