Numerical modelling of contracted sharp crested weirs

Duru, Aysel

doi:10.1201/b21902-103

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…Similarly, different discharge equations are used if a weir is operating freely, as in stages 3 and 4, or if it is submerged, as in stage 5. Although in reality the gate and weir flows will interact [63][64][65], the interaction is ignored in the present study, and the gate and weir discharges are simply added together.…”

Section: Conceptual Modelmentioning

confidence: 99%

Modelling the Impact of Leaky Barriers with a 1D Godunov-Type Scheme for the Shallow Water Equations

Leakey

Hewett

Glenis

et al. 2020

Water

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There is increasing interest in distributing small-scale interventions across the landscape as an alternative means of reducing flood risk. One such intervention, the leaky barrier, is introduced in channels to slow down high flows and encourage temporary storage on the floodplain. While these barriers have been implemented widely, there is still resistance to their use at the scales required to impact significantly on flood risk, at least partially due to an evidence gap. In particular, there is no standard method for representing leaky barriers in hydraulic models. This study sets out a methodology for developing mathematical models which capture the hydraulics of leaky barriers accurately, allowing key questions about their combined behaviour in catchments to be answered. A 1D Godunov-type scheme is set up and leaky barriers incorporated with internal boundary conditions. This model is tested against benchmarks from the literature and new steady-state data, and then run predictively on transient cases. The method will help to answer key questions about the optimal leakiness of small-scale interventions, the limits to their usefulness, and how combinations of barriers may or may not cause synchronisation problems when the effect of multiple barriers is aggregated.

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Section: Conceptual Modelmentioning

confidence: 99%

Modelling the Impact of Leaky Barriers with a 1D Godunov-Type Scheme for the Shallow Water Equations

Leakey

Hewett

Glenis

et al. 2020

Water

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“…It is initially necessary to determine the optimum simulation conditions for the geometry under consideration. Hence, to consider cell size, turbulence model and upstream canal length effects, a CFD analysis was performed with defined upstream water depth (Duru et al, 2016). After the optimum model parameters were set with the given physical conditions, the model was rerun for different water depths.…”

Section: Problem 1 (Contracted Sharp-crested Weir)mentioning

confidence: 99%

Numerical modelling of contracted sharp‐crested weirs and combined weir and gate systems

Altan‐Sakarya

Kökpinar

Duru

2020

Irrigation and Drainage

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Discharge measurement and control structures are widely employed in hydraulic engineering applications. The objective of this study is to numerically investigate the modelling of two different structures, namely sharpcrested weirs as Problem 1 and combined weir and gate systems as Problem 2. The research methodology herein is based on the comparison of results of numerical simulations with experimental data for both problems separately. For the purpose of performing numerical simulations, the Reynolds-averaged Navier-Stokes (RANS) equations are solved by finite volume formulation using commercially available Flow-3D software. Assessment of empirical data and numerical findings for both problems reveals that discharge rates agree reasonably well. In addition, using the capabilities of numerical modelling, weir and gate discharge coefficients in the combined system are calculated separately which were not easy to obtain in experimental studies. It is seen that gate and weir discharge coefficients of the combined system are different and higher than the corresponding coefficients of the individual systems. K E Y W O R D S combined weir and gate system, discharge measurement, Flow-3D, numerical simulation Résumé Les structures de mesure et de contrôle du débit sont largement utilisées dans les applications de génie hydraulique. L'objectif de cette étude est d'étudier numériquement la modélisation de deux structures différentes, à savoir des seuils à crête vive comme problème 1 et des systèmes de seuil et de barrière combinés comme problème 2. La méthodologie de recherche ici est basée sur la comparaison des résultats de simulations numériques avec des données expérimentales pour les deux problèmes séparément. Dans le but d'effectuer des simulations numériques, les équations de Reynolds-averaged Navier-Stokes (RANS) sont résolues par formulation de volumes finis à l'aide du logiciel Flow-3D disponible dans le commerce. L'évaluation des données empiriques et des résultats numériques pour les deux problèmes révèle que les taux de rejet concordent assez bien. De plus, en utilisant les capacités de la *Modélisation numérique des seuils à crête vive contractés et des systèmes combinés de seuils et de vanes.

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“…The discharge coefficient was founded for different flow cases showing the discharge coefficients for all three cases of flow increases with the increase of the head over the weir crest. (Duru, 2014) [10] conducted numerical modeling for contracted sharp crested weirs and combined weir-gate structure using Flow 3D, results show that computational fluid dynamic software is a powerful tool for simulating hydraulic problems related to the measurement structures of flow. A series of experimental models of combined curved weir and rectangular gate were conducted by (Obead and Hamad, 2014) [11], these models that the weir angle has a significant influence on the combined flow through the weir-gate system.…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Performance for Combined Weir-Gate Structure

Hussein

Jalil

2020

Tikrit j. eng. sci.

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Combined hydraulic structure play an important role in controlling flow in open channels. This study was based on experimental and numerical modeling investigations for combined hydraulic structure. For this purpose three physical models of combined sharp crested trapezoidal weir with bottom opening and one physical model of sharp crested trapezoidal weir separately were used and tested by running eight different flow rates over each model. In which three configurations of bottom opening were tested; the first configuration is a rectangular gate while other two configuration were trapezoidal with two different side slopes of (1V:4H) and (1V:2H). The water surface profiles passing through weir-gate system were measured for all thirty two runs of all models which show uniform flow at 2.11h from the upstream of weir. The commercial computational fluid dynamic software ANSYS CFX was used to simulate flow numerically. The verification of the numerical model was based on water surface profiles and discharge which showed acceptable agreement. Also, the results showed that discharge coefficient Cd varies from (0.52-0.58). Furthermore, it was shown that both models with trapezoidal gate pass a higher discharge of flow than the model with rectangular gate with average percentage increase of discharge (40.78% and 19.40%) for trapezoidal side slopes (1H:2V and 1H:4V) respectively. In addition, the combined system with milder trapezoidal side slopes of bottom opening had a better performance for discharging weir flow which is about 40% as compared with traditional one. Finally, the empirical equations for stage-discharge relationship were estimated for all models and discharge coefficients were estimated for all runs.

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Numerical modelling of contracted sharp crested weirs

Cited by 3 publications

References 10 publications

Modelling the Impact of Leaky Barriers with a 1D Godunov-Type Scheme for the Shallow Water Equations

Modelling the Impact of Leaky Barriers with a 1D Godunov-Type Scheme for the Shallow Water Equations

Numerical modelling of contracted sharp‐crested weirs and combined weir and gate systems

Hydraulic Performance for Combined Weir-Gate Structure

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