Numerical Modelling of Air-Water Flows over a Stepped Spillway with Chamfers and Cavity Blockages

Li, Shicheng; Yang, James; Li, Qiulin

doi:10.1007/s12205-020-1115-x

Cited by 13 publications

(5 citation statements)

References 38 publications

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“…Qian et al [20] compared four turbulence models (i.e., realizable k-ε model, SST k-ε model, ν 2 -ƒ model and LES model) and considered the realizable k-ε model as the most efficient in simulating skimming flows over stepped spillways. The realizable k-ε model was also successfully applied to simulating the skimming flow over a V-shaped stepped spillway by Bai et al [21] and the stepped spillway with chamfers and cavity blockages by Li et al [22].…”

Section: Methodsmentioning

confidence: 99%

Effects of Converging Sidewalls on Skimming Flow over Converging Stepped Spillway

et al. 2022

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A numerical study is conducted for converging stepped spillways with various spillway slopes, sidewall convergence and flow discharges to understand the influences of converging sidewalls on skimming flows. Compared with the traditional uniform-width stepped spillway, the converging sidewall changes the skimming flow features by generating standing waves on the free-surface, curving the mainstream streamlines and squeezing and distorting the bottom rotations. For free-surface, mainstream and bottom rotations, the width of disturbed regions by the converging sidewall varies, with that for bottom rotations being 1.5 times that for mainstream and 3 times that for free-surface. The variation rules of disturbed region widths along the spillway are obtained, and the maximum widths increase as the convergence angle and incoming flow discharge increase, and the spillway slope decreases. Three equations are established for predicting the maximum widths of disturbed regions for free-surface, mainstream and bottom rotations of skimming flow. Since the disturbed region of skimming flow generated by the converging sidewall is characterized by strong standing waves, high flow velocity and low air concentration, appropriate engineering measurements should be taken for the disturbed region to meet the challenges to overtopping, energy dissipation and cavitation control.

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Section: Methodsmentioning

confidence: 99%

Effects of Converging Sidewalls on Skimming Flow over Converging Stepped Spillway

et al. 2022

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“…With an increase in q, β shows an upward trend. Another approach is also used for assessment of energy dissipation in hydraulic structures [31,32]. The energy dissipation rate (β) reads…”

Section: Energy Dissipationmentioning

confidence: 99%

Evaluation of Pool-Type Fish Passage with Labyrinth Weirs

Yang

Ansell

2022

Sustainability

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Due to the construction of dams and sluices, habitat fragmentation of riverine species is an issue of concern in hydropower projects. An artificial fishway aims to restore flow connectivity and facilitate migration. As an alternative to the conventional layout with straight walls, labyrinth layouts are introduced, consisting of either triangular, trapezoidal, or rectangular weirs. Three-dimensional CFD simulations are performed to examine their influences on the fishway hydraulics. The labyrinth layouts exhibit an appreciable three-dimensional flow structure in a pool, featuring flow fluctuations in both cross- and along-channel directions, which is indicative of the potential for multiple species with distinct swimming preferences. The streamwise reduction in mean flow velocity is correlated with the Froude number, with the labyrinth weirs leading to a somewhat lower reduction than the conventional one. The dimensionless pool water depth declines with specific flow discharge. The turbulence kinetic energy is the lowest in the triangular layout and the vorticity in the conventional one. Among the labyrinth layouts, the differences in volumetric power dissipation are small. An equation is developed for dissipation estimation. All the labyrinth layouts generate higher energy loss than the conventional one. With optional weir configurations, the findings provide reference for engineering design.

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“…For example, the numerical studies on stepped spillways have increased daily. The researchers used various step and threshold geometries or chute angles to analyze the stepped spillway flow dynamics and energy dissipation (Tabbara et al 2005;Shahheydari et al 2015;Mohammad et al 2016;Hekmatzadeh et al 2018;Li et al 2018Li et al , 2020Ashoor & Riazi 2019;Reeve et al 2019;Arjenaki & Sanayei 2020;Ghaderi et al 2020Ghaderi et al , 2021Ikinciogullari 2021).…”

Section: Introductionmentioning

confidence: 99%

Stepped spillway design for energy dissipation

Ikinciogullari

2023

Water Supply

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Important water structures known as stepped spillways are used to dissipate energy, aerate rivers, and reduce the cost of the downstream pool. The aim of this study is to increase the energy dissipation rate by proposing an alternative design to the flat stepped spillways, which are frequently used in practice. For that reason, the Circular Stepped Spillway (CSS) has been constructed and numerically investigated in this paper. The energy dissipation rate of the CSS and the flat stepped spillway has been compared using three different models and discharges. According to the simulation findings, the CSS performs better as the step radius gets smaller. The CSS models with step depths of 0.50, 1.50, and 2.50 cm have dissipated up to 21.4, 38, and 50.7% more energy than the flat stepped spillway, respectively.

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Numerical Modelling of Air-Water Flows over a Stepped Spillway with Chamfers and Cavity Blockages

Cited by 13 publications

References 38 publications

Effects of Converging Sidewalls on Skimming Flow over Converging Stepped Spillway

Effects of Converging Sidewalls on Skimming Flow over Converging Stepped Spillway

Evaluation of Pool-Type Fish Passage with Labyrinth Weirs

Stepped spillway design for energy dissipation

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