Combined-free flow over weirs and below gates

Negm, Abdelazim M.; Al-Brahim, A.M.; Alhamid, A.A.

doi:10.1080/00221680209499950

Cited by 66 publications

(26 citation statements)

References 6 publications

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“…(9&10) shows that the value of discharge coefficient Cd decreases with the increase of , and its value increases with the increase distance between baffles. Comparing figure (9) with figure (10) it can be noted that the channel slope has a negative effect on the value of Cd which shows less values of discharge coefficient Cd for the same geometric combinations.…”

Section: Variation Of (Cd) With the Ratiomentioning

confidence: 90%

Laboratory Study of Flow Characteristics Through three Baffle – Sluice Gates.

Al-mallah¹,

Hayawi²

2019

(AREJ)

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The main objective of this study is to investigate the experimentally the coefficient of discharge for three baffle sluice gates and compared with single gate. The channel slope was changed tow times (0, 0.0075). For this purpose three baffle sluice gates were made from fibber class with (1cm) thick, (30cm) wide and (15,25,30)cm height for first, second and third gate respectively. The three gates have been sharp edge from the top and bottom with 2mm thick .The distance between the three parallel baffle gates were changed three times (2, 3.5, 5) cm. The analysis of results showed that discharge coefficient Cd in horizontal channel is larger than its value in inclined channel with direction of flow and the change in space between gates didn ' t cause an important difference between values of discharge coefficient Cd. The values of Cd were between (0.561-0.736) for horizontal channel and three gates, while when the channel inclined the values of Cd were between (0.523-0.662) for three gates.

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Section: Variation Of (Cd) With the Ratiomentioning

confidence: 90%

Laboratory Study of Flow Characteristics Through three Baffle – Sluice Gates.

Al-mallah¹,

Hayawi²

2019

(AREJ)

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“…Rajaratnam and Humphries 1982, Alhamid 1999, Negm et al 2002, Heidarpour and Chamani 2006. Even though sharp-crested weirs are related to discharge measurement, they are used in hydraulic structures as channel control and are also applied as the basis of expensive structures design such as the spillway (Vischer and Hager 1998).…”

Section: Introductionmentioning

confidence: 99%

Discharge coefficient of sharp-crested weirs using potential flow

Afzalimehr

Bagheri

2009

Journal of Hydraulic Research

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Sharp-crested weirs are used in hydraulic structures for accurate discharge measurement. Using a plane vertical plate perpendicular to the flow direction and applying the theory of complex variables, an equation is developed for estimating the discharge coefficient of rectangular sharp-crested weirs by the potential flow theory. The results reveal that the ratio of overflow head to the weir height can be presented by a power equation to obtain a correction factor to determine the discharge coefficient. Experimental data indicate that the suggested equation for the discharge coefficient gives reasonable results for a large range of relative overflow depths. RÉSUMÉLes déversoirs à arête vive sont utilisés dans les ouvrages hydrauliques pour la mesure précise du débit. A l'aide d'une plaque plane verticale perpendiculaire à la direction de l'écoulement et en appliquant la théorie des variables complexes, une équation est développée pour l'estimation du coefficient de débit des déversoirs à arête vive rectangulaires avec la théorie des écoulements potentiels. Les résultats révèlent que le rapport de la hauteur de débordement à la hauteur du déversoir peut être présenté par une équation puissance pour obtenir un facteur de correction déterminant le coefficient de débit. Les données expérimentales indiquent que l'équation suggérée pour le coefficient de débit donne des résultats raisonnables pour une large gamme de profondeurs relatives de débordement.

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“…Moreover, they reported that the maximum scour depth place was transferred from flow upstream to downstream by increasing the flow discharge [4]. Negm et al (2002) investigated a free-state combined flow for rectangular weir-gate with equal compression. The concluded that flow discharge coefficient had a direct relation with dimensionless parameters of total upstream head ratio to gate openness and the ratio of the head over the structure to weir and gate.…”

Section: Introductionmentioning

confidence: 99%

“…The concluded that flow discharge coefficient had a direct relation with dimensionless parameters of total upstream head ratio to gate openness and the ratio of the head over the structure to weir and gate. Also, it was found that flow discharge coefficient had a reverse relation with the ratio of weir-gate distance to gate openness [5]. Dey and Sarkar (2006) carried out an experimental study on sediment beds scour in even and uneven states in downstream of aprons with different lengths.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimension Numerical Simulation of Scour Temporal Changes due to Flow in the Downstream of Combined Weirs and Gate Model

2017

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Most of weirs create a region with relatively static water in upstream, which can be the place of sediments and wastes deposition in water. Sediments accumulation in upstream changes flow conditions. In this case, combined weir and gate can be propounded as a useful solution. In the present paper, Flow3D was used to numerically simulate temporal changes of scour in combined free flow over weirs and below gates. Numerical modeling was run after fully preparing and the obtained data was analyzed under three-dimensional conditions. Comparing experimental and numerical results with data fitness revealed that determination coefficient (R 2 ) of the numerical model results to the experimental model results is 0.94. Also, it was found that the relative error of the numerical model results relative to the experimental results equals 7.36%. Further, it was found that at the start of computations in the numerical model, compared to the end of running the model, the turbulent energy dissipation was decreased to 38% and decreasing the turbulent energy dissipation led to the creation of scour hole balance in the numerical model.

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Combined-free flow over weirs and below gates

Cited by 66 publications

References 6 publications

Laboratory Study of Flow Characteristics Through three Baffle – Sluice Gates.

Laboratory Study of Flow Characteristics Through three Baffle – Sluice Gates.

Discharge coefficient of sharp-crested weirs using potential flow

Three-Dimension Numerical Simulation of Scour Temporal Changes due to Flow in the Downstream of Combined Weirs and Gate Model

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