Free-surface stretching-sustained intake vortices

Carriveau, Rupp; Kopp, Gregory A.; Baddour, R. E.

doi:10.1080/00221686.2009.9522024

Cited by 15 publications

(5 citation statements)

References 27 publications

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“…They studied the flow pattern where strong free surface vortices were present in the vicinity of the pump intake. Carriveau et al (2009) investigated the formation mechanisms of vortices at deep hydraulic intakes. They found that vortices can form at submerged intakes in different distinct manners depending on the magnitude of the submergence parameter.…”

Section: Introductionmentioning

confidence: 99%

Velocity field in a reservoir in the presence of an air-core vortex

Sarkardeh

Jabbari

Zarrati

et al. 2014

Proceedings of the Institution of Civil Engineers - Water Manag

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The velocity field in a reservoir in the presence of surface vortices was experimentally studied. Experiments were performed with a horizontal intake and with a constant submerged depth and two different intake Froude numbers.The spline smoothing method was used to improve the graphical presentation of the measured data. Results are presented and compared in different horizontal sections in the reservoir. A downward conical flow over the intake axis and an upward one below the intake axis were observed in the reservoir. Finally, the prevailing domains of vertical and horizontal velocities were determined.

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Section: Introductionmentioning

confidence: 99%

Velocity field in a reservoir in the presence of an air-core vortex

Sarkardeh

Jabbari

Zarrati

et al. 2014

Proceedings of the Institution of Civil Engineers - Water Manag

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“…where p is the fluid pressure, G x , G y , G z are body accelerations in the coordinate direction x, y, z; f x , f y , f z are viscous accelerations in three directions and is related to the volume of fluid, defined by Equation (7). For modeling of free surface profile, the VOF technique based on the volume fraction of the computational cells has been used.…”

Section: Methodsmentioning

confidence: 99%

“…The cross-flow test showed significant effects of nonuniform pump-approach flow on pump-throat velocity distributions [6]. Carriveau et al (2009) examined the mechanism of vortex formation at hydraulic intakes and revealed two distinct groups of free surface vortices. They defined the stretching-sustained submergence and based the vortex classification on the magnitude of this parameter [7].…”

mentioning

confidence: 99%

“…Carriveau et al (2009) examined the mechanism of vortex formation at hydraulic intakes and revealed two distinct groups of free surface vortices. They defined the stretching-sustained submergence and based the vortex classification on the magnitude of this parameter [7]. Roshan et al (2009) studied the formation and prevention of vortices at hydraulic model of Godar-e-Landar dam.…”

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confidence: 99%

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Experimental and numerical investigation on effect of trash rack on flow properties at power intakes

et al. 2020

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In the present experimental and numerical research, the flow behavior in a reservoir and horizontal water intake was analyzed in the presence of surface vortices. To do so, velocity field, vortex strength, and Reynolds number in different horizontal sections in the reservoir and the energy loss and entrained air volume at horizontal intake pipe at three different relative submerged depths (S/D = 1, 1.5 and 2) and five intake Froude numbers (Fr = 0.8, 1.0, 1.2, 1.4, and 1.6) were investigated by installing two trash racks with 64% and 70% openings and one intake without trash rack. The velocity field and vortex strength were measured using Particle Tracking Velocimetry. Reynolds number, velocity, energy loss, and entrained air volume at horizontal intake pipe were computed by numerical simulations. The commercially available computational fluid dynamics program Flow‐3D, was used for the numerical modeling. Numerical simulations were validated by the experimental data. The experimental tests revealed that trash rack presence has a significant effect on reducing the vortex strength and velocity on the water surface. The vortex strength was decreased by 11% and 16% in the trash racks with 70% and 64% opening, respectively. Energy loss clearly increased with the installation of a trash rack. Energy loss in the trash rack with 70% opening was approximately 19–26%. In addition, some relationships were provided for calculation of vortex strength, velocity, and local energy loss in the water intake, which are in good agreement with the studies in the literature.

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“…Wang et al [18] modified, for given water depth, the intake configuration to weaken the air-core vortex in front of a tunnel intake. Carriveau et al [19] and Sarkardeh et al [20] examined experimentally the effects of intake head-wall slope and trash-rack installation on the vortex strength reduction. The use of anti-vortex plates to improve the critical submergence condition was also found in Reference [21] for a vertical intake.…”

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confidence: 99%

The Tale of an Intake Vortex and Its Mitigation Countermeasure: A Case Study from Akkats Hydropower Station

Yang

Andreasson

Högström

et al. 2018

Water

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The upgrade of Akkats power station in Sweden included a new, separate waterway for the addition of a 75 MW generating unit. The vertical intake of its headrace was formed by means of lake tapping. A physical model was used to help understand the blasting process involving fragmented rock, water, air, and gas. Upon commissioning of the unit, swirling flows occurred unexpectedly at the intake, which gave rise to negative consequences including limitations in power output. Echo-sounding showed that the blasted piercing resulted in an irregular intake. A hydraulic model, as part of the design process, was built to examine potential countermeasures for vortex suppression. The final solution was a segmented barrier between the intake and the dam. It effectively suppressed the intake flow circulations; only minor intermittent vortices were left. The fabricated steel segments were anchored into the bedrock, stretching to 1.0 m below the lowest legal reservoir level. The local intake headloss was also reduced. The implemented solution was tested under full turbine loading and the result was satisfactory. Even during winter seasons with ice cover above the wall, the power station ran normally. The case study is expected to provide guidance for solving similar problems with vortex formation.

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Free-surface stretching-sustained intake vortices

Cited by 15 publications

References 27 publications

Velocity field in a reservoir in the presence of an air-core vortex

Velocity field in a reservoir in the presence of an air-core vortex

Experimental and numerical investigation on effect of trash rack on flow properties at power intakes

The Tale of an Intake Vortex and Its Mitigation Countermeasure: A Case Study from Akkats Hydropower Station

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