Numerical simulation of anti-vortex devices at water intakes

Rabe, Behrouz Khadem; Najafabadi, Seyyed Hossein Ghoreishi; Sarkardeh, Hamed

doi:10.1680/jwama.16.00051

Cited by 23 publications

(10 citation statements)

References 19 publications

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“…Their numerical simulations were validated with experimental data. Their analysis on the type of vortex and radial velocity was in good agreement with the experimental results [23]. Khadem Rabe et al (2017) numerically simulated the air-core vortex at an intake.…”

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confidence: 66%

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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confidence: 66%

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

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“…The numerical model data is the output of the STAR-CCM + . Khadem Rabe et al [17,18] used the STAR-CCM + in a study of the simulation of the vortex core and compared their results with different experimental and numerical studies. Therefore, it could be deduced that STAR-CCM + software has reasonable accuracy in simulating free-surface vortices.…”

Section: Verification Of the Numerical Modelmentioning

confidence: 99%

“…They concluded that cavitation would increase the boundary layer of the stream and exacerbate the vortex air-core. Khadem Rabe et al [17,18] conducted numerical simulations to examine the behavior of the flow when the vortex air-core was pulled into the basin. In this research, tangential, radial, and axial velocity components, and water surface profiles were evaluated for an in-depth understanding of the flow patterns and to work out the depth of critical submersion.…”

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confidence: 99%

Elimination of vortices by wave generation as a hydraulic anti-vortex method

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Tabatabai

Sarkardeh

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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Free-surface vortex formation is one of the undesirable hydraulic phenomena that may occur at intakes during the dewatering reservoir. This research is meant to investigate the effect of waves on formed vortices in vertical intakes numerically by applying STAR-CCM + software. The simulation was conducted to model the free surface and turbulence by volume of fluid and large eddy simulation methods, respectively. Sensitivity analysis was undertaken on different mesh sizes to select appropriate mesh dimensions. Then, verification was performed by Sun and Liu (J Hydraul Res 53:787-796, 2015) experimental data. Results showed that waves reduce or eliminate hydraulic parameters of the formed vortices such as vortex strength, tangential, radial, and axial velocity components. The reduction appeared by average values of 32%, 30%, 22%, and 25% in vortex strength, tangential, radial, and axial velocity components, respectively. Waves also led to decrement in the length and diameter of air-core of vortices about 45% for the former and more than 50% for the latter. In addition, it was concluded that the smaller the waves, the greater their effects would appear on the elimination of the vortex phenomenon. Finally, a relationship between the wave properties, as a hydraulic approach to anti-vortex, and vortex parameters was developed. Keywords Vertical intake • Surface wave • Free-surface vortex • Numerical simulation • STAR-CCM+ List of symbols P Pressure (kgm −1 s −2) u Velocity (ms −1) f i External force (kgms −2) g Gravity force (ms −2) V e Tangential velocity (ms −1) V r Radial velocity (ms −1) V z Axial velocity (ms −1) r Vortex radius (ms −1) Z Height from free surface (m) k T Turbulence kinematic energy σ Coefficient of surface tension Density (kgm −3) Dynamic viscosity (kgm −1 s −1) Reynolds-stress tensor (kgm −1 s −2) Kinematic viscosity (m 2 s −1) Eddy viscosity (m 2 s −1) e Effective viscosity (m 2 s −1) Γ Circulation (m 2 /s) ⃗ Angular velocity (rads −1) 2 r m V Γ in max Dimensionless parameter of tangential velocity (−Vrrm) e max Dimensionless parameter of radial velocity (V z r 2 m e z) max Dimensionless parameter of axial velocity

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“…Unlike previous model tests conducted at a reduced scale, those presented by Kucukali and Hassinger (2018) were performed at a scale of 1:1 to avoid viscosity scale effects. In the tested fish pass with a bed slope of 4%, multiple continuous migration corridors were found, without obstructions for the fish to overcome or flow regime changes.Complementary to laboratory experiments, advanced 3D numerical modelling was used by Khadem Rabe et al (2018) to simulate the flow near an anti-vortex system at a water intake. Although avoiding vortices at water intakes is of utmost importance (as they can suck surface debris and air into the pressurised flow system), considerable gaps in knowledge remain regarding the prediction and characterisation of vortex generation.…”

mentioning

confidence: 99%

“…Complementary to laboratory experiments, advanced 3D numerical modelling was used by Khadem Rabe et al (2018) to simulate the flow near an anti-vortex system at a water intake. Although avoiding vortices at water intakes is of utmost importance (as they can suck surface debris and air into the pressurised flow system), considerable gaps in knowledge remain regarding the prediction and characterisation of vortex generation.…”

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confidence: 99%

Editorial

Dewals

2018

Proceedings of the Institution of Civil Engineers - Water Manag

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This issue of Water Management brings you five inspiring papers on a broad spectrum of topics, ranging from weirs to innovative fish pass, water intakes, urban drainage networks and rockfill dams. These papers showcase the variety of tools and methods deployed in hydraulic engineering, such as advanced laboratory measurements, complex threedimensional (3D) numerical simulations and optimisation techniques, as well as good practice derived from field experience. These tools and methods synergistically combine to make our profession, water management, uniquely stimulating from both the practical and the scientific perspectives.In their Briefing article, Kitchen et al. (2018) draw attention to a recently published technical guide that provides guidance on the design and management of weirs. Weirs are common structures in the UK as well as overseas. They provide a number of services by enabling water level management for shipping, flood control, flow measurement, channel stabilisation, or hydropower, among others. However, weirs raise safety issues for water-and land-users; they may induce geomorphological impacts and they impede fish migration. Therefore, the design, operation, maintenance and adaptation of weirs require a holistic approach addressing the hydraulic, structural, environmental and safety components of weir performance. Such an approach is presented in the new guide, together with guidance on alternatives to weirs (for example, rock ramps) as well as on weir removal, which may be considered as an option for weirs that have ceased to function properly or are not needed anymore. Weir removal is beneficial in terms of fish pass, sediment continuity and river restoration as a whole; but caution must be taken in assessing and mitigating possible geomorphological consequences such as bed degradation and bank undermining upstream.Fish migration in a regulated water course may be enhanced by means of fish pass. Kucukali and Hassinger (2018) present rigorous flow and turbulence measurements in an innovative and cost-effective fish pass, which enables migration for a wide range of fish species characterised by high to low swimming capacity. The fish pass combines the features of traditional baffle fishways with those of brush-furnished fishways, without the need for resting pools (Kucukali and Hassinger, 2015). Unlike previous model tests conducted at a reduced scale, those presented by Kucukali and Hassinger (2018) were performed at a scale of 1:1 to avoid viscosity scale effects. In the tested fish pass with a bed slope of 4%, multiple continuous migration corridors were found, without obstructions for the fish to overcome or flow regime changes.Complementary to laboratory experiments, advanced 3D numerical modelling was used by Khadem Rabe et al. (2018) to simulate the flow near an anti-vortex system at a water intake. Although avoiding vortices at water intakes is of utmost importance (as they can suck surface debris and air into the pressurised flow system), considerable gaps in knowledge remain regarding ...

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Numerical simulation of anti-vortex devices at water intakes

Cited by 23 publications

References 19 publications

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

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

Elimination of vortices by wave generation as a hydraulic anti-vortex method

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