Energy Dissipation in Stepped Spillway Equipped with Inclined Steps Together with End Sill

Hamedi, Amirmasoud; Malekmohammadi, Iman; Mansoori, Abbas; Roshanaei, Hamed

doi:10.1109/cicn.2012.109

Cited by 14 publications

(5 citation statements)

References 7 publications

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“…It was found that increase in stairs length and heights, cause an increase in energy dissipation. Hamedi et al [7] conducted an experimental procedure and laboratory work to scrutinize whether the rate of energy loss on stepped spillway using Inclined steps together with end sill increases. Results showed that using inclined steps together with end sill have considerable effects on both nappe and skimming flows, however, energy dissipation in nappe flows is greater than that in skimming flows.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional analysis of the performance of circular stepped spillways in the skimming flow regime

Ghaderi,

Ebrahimnezhadian,

Mollazadeh

2024

J Braz. Soc. Mech. Sci. Eng.

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By creating an artificial rough bed, stepped spillways increase energy dissipation during the spillway and reduce the risk of cavitation and the dimensions of the stilling basin. Combining stepped spillways with labyrinth spillways in order to improve their performance can be an attractive idea. Therefore, in this research, the hydraulic characteristics of the flow, the amount of energy dissipation and the residual energy of the flow downstream of the stepped spillway with a circular labyrinth configuration, with different numbers of cycles, were compared with the conventional stepped spillway. Validation of the numerical model was done using the results of the physical model. Four three-dimensional configurations of stepped spillway including: conventional stepped, two-, three-, and four-cycle circular labyrinth were modeled using OpenFOAM open source for the skimming flow regime. In order to simulate the flow, InterFOAM solver and RNG K  − turbulence model were used. The results of the numerical model showed that the combination of the labyrinth spillway with the stepped spillway causes an increase of 7.4, 28 and 18.3 percent of energy dissipation in circular forms of two, three and four cycles compared to its conventional type for a constant discharge and yc/h=1.68. Therefore, among the circular labyrinth configurations, the three-cycle form (3CSS) has the highest dissipation rate. In addition, in the three-cycle circular labyrinth configuration, compared to other conventional and labyrinth configurations, it has resulted in less negative pressure in the upper half of the vertical face of the steps.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional analysis of the performance of circular stepped spillways in the skimming flow regime

Ghaderi,

Ebrahimnezhadian,

Mollazadeh

2024

J Braz. Soc. Mech. Sci. Eng.

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“…Chinnarasri and Wongwises [9] noted that the rate of energy dissipation on the flat stepped chute was significantly lower than that on steps with end sills for chute slopes of 45 degrees. Hamedi et al [10] investigated whether the energy loss rate of stepped spillways increases as a result of using end sills and inclined steps. Inclined steps with various slopes and end sills with various thicknesses, heights, and angles upward are used in this experiment to better understand their effects on relative energy loss.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Investigation of Energy Dissipation for Stepped Spillways with Different Flow Conditions

Albank¹,

Khassaf²

2023

MMEP

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The stepped spillway is the most effective hydraulic structure for dissipating energy downstream of the spillway crest. This paper investigates the energy dissipation rate on physical models of traditional steps at downstream angles (25˚, 35 , 45 ) in which each angle was modelled with two different heights of steps (45, and 90 mm). Experimentation has been done for plain steps, and steps with end sill steps of a thickness of 15 mm. The results, which are supported by dimensional considerations, show that the critical depth of flow passing over the spillway to the step height yc/h, the number of steps N, and the slope of the stepped spillway are the parameters that affect energy dissipation. The results show also that the relative energy loss on pooling steps dissipates more energy than on flat steps by about 4.6%.

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“…The improvement is done through increasing the dissipation of kinetic energy and reducing the negative effect of pressure values by re-enhancing distribution. (e.g., ChaiyuthChinnarasri&Wongwises, 2004;Al-Lami ,2008;Bung, 2010;Hamedi et al, 2012;Felder & Chanson, 2013 ;Ojaimi, 2013;Ahmad et al, 2014 ;Al-Shakur et al, 2014;Kathirvelan et al, 2015) [6][7][8][9][10][11][12][13][14]. The structural development that was adopted for these studies included; inclined upward steps, labyrinth step shape, end sills, adding baffle row or blocks at the downstream end of the step, pooled step, and Macro-roughness systems to reduce the length of inception point which will almost mitigate the risk of cavitation.…”

Section: Introductionmentioning

confidence: 99%

Distribution of Pressures on Modified Stepped Spillway by Using Toothed-Steps

Maatooq¹,

Jasim²

2021

ETJ

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 A new stepped spillway shape was used in experimental work under the skimming flow regime by adding block (tooth) on the step.  The tooth-stepped spillway reduces the positive and negative pressure on steps close to the crest by a large amount and especially at high discharge.  When the spacing between tooth increase the pressure along the chute will have bad distribution compare to the traditional model.In the present study a new steeped spillway shape at which "toothed steps" have been adopted instead of traditional steps to enhance the amount and distribution of water pressure along the chute of the stepped spillway. Experiments were conducted under a skimming flow regime, on five physical models of spillway one of which consisted of traditional steps used as a base model. For all investigated models, the chute angle was 45° with fourteen steeps each of 3cm height. Generally, the results show that the new shape models enhance the pressure distribution and reducing the potential for negative pressures along the chute, as well as, reducing the values of positive pressures that usually impact the tread. Specifically, close to the crest, the differences in pressure values being clearly large between the toothed steps modelsand the traditional steps. The new configurations of steps reduce the positive pressures between 116.66% to 1.28 % and the negative pressures were generally close to zero.

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Energy Dissipation in Stepped Spillway Equipped with Inclined Steps Together with End Sill

Cited by 14 publications

References 7 publications

Three-dimensional analysis of the performance of circular stepped spillways in the skimming flow regime

Three-dimensional analysis of the performance of circular stepped spillways in the skimming flow regime

An Experimental Investigation of Energy Dissipation for Stepped Spillways with Different Flow Conditions

Distribution of Pressures on Modified Stepped Spillway by Using Toothed-Steps

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