Ecoulement et dissipation sur les déversoirs en gradins de gabions

Peyras, Laurent; Royet, Paul; Degoutte, Gérard

doi:10.1051/lhb/1991003

Cited by 33 publications

(27 citation statements)

References 3 publications

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“…Their observations indicated nappe flows for d c =h < 0.6-0.7 depending upon the chute slope, with skimming flows for larger flow rates (Peyras et al 1991).…”

Section: Flow Regimesmentioning

confidence: 98%

Hydraulics, Air Entrainment, and Energy Dissipation on a Gabion Stepped Weir

Wüthrich

Chanson

2014

J. Hydraul. Eng.

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In the last decades the design of stepped spillways regained some interest because of their suitability with new construction methods including gabions. The hydraulic performances of gabion stepped weirs were investigated experimentally in terms of the flow patterns, air-water flow properties, and energy dissipation. A laboratory study was conducted in a 26.6°slope (1V:2H) and 0.10-m step height facility, with both smooth impervious and gabion steps. The visual observations highlighted the seepage flow through the gabions, inducing a modification of the cavity flow especially in the skimming flow regime. In skimming flows, higher velocities were measured at the downstream end of the gabion stepped chute, associated with smaller energy dissipation rates and lower friction factors, compared to the smooth impervious stepped chute data.

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“…Their observations indicated nappe flows for d c =h < 0.6-0.7 depending upon the chute slope, with skimming flows for larger flow rates (Peyras et al 1991).…”

Section: Flow Regimesmentioning

confidence: 98%

Hydraulics, Air Entrainment, and Energy Dissipation on a Gabion Stepped Weir

Wüthrich

Chanson

2014

J. Hydraul. Eng.

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“…It shows that all data gave a consistent trend. Note that the graph does not include the data of [35] and [33] for inclined steps, nor pooled step data reported by [10].…”

Section: Experimental Flow Conditionsmentioning

confidence: 99%

Energy dissipation, flow resistance and gas-liquid interfacial area in skimming flows on moderate-slope stepped spillways

Felder

Chanson

2009

Environ Fluid Mech

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With the re-evaluation and revision of a number of design floods, several embankment overtopping protection systems have been developed and a common technique is the construction of a stepped spillway on the downstream slope. For such moderate slope stepped channels, detailed air-water flow measurements were performed in a large facility with a focus on the rate of energy dissipation, flow resistance, air-water interfacial areas and re-aeration rates. Past and present experimental results showed a significant aeration of the flow. The median dimensionless residual head was about 3 × d c for the 21.8 • sloping chute and smaller than that for flatter slopes (θ = 3.4 • and 15.9 • ). The flow resistance results yielded an equivalent Darcy friction factor of about 0.25 implying a larger flow resistance for the 21.8 • slope angle than for smaller slope angles. The re-aeration rate was deduced from the integration of the mass transfer equation using measured air-water interfacial areas and air-water flow velocities. The results suggested an increasing re-aeration rate with increasing rate of energy dissipation. The stepped invert contributed to intense turbulence production, free-surface aeration and large interfacial areas. The experimental data showed however some distinctive seesaw pattern in the longitudinal distribution of air-water flow properties with a wave length of about two step cavities. While these may be caused by the interactions between successive adjacent step cavities and their interference with the free-surface, the existence of such "instabilities" implies that the traditional concept of normal flow might not exist in skimming flows above moderate-slope stepped spillways.

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“…Recently ANDRE et al (2001) suggested an alternance of pooled steps and flat steps for maximum energy dissipation. PEYRAS et al (1991) demonstrated greater energy dissipation with inclined upward steps. All these techniques add considerable structural loads to the stepped structure and might not be economical.…”

Section: Energy Dissipation Enhancement: Prototype and Laboratory Expmentioning

confidence: 94%