Effects of different configurations of sloping crests and upstream and downstream ramps on the discharge coefficient for broad-crested weirs

Nourani, Bahram; Arvanaghi, Hadi; Salmasi, Farzin

doi:10.1016/j.jhydrol.2021.126940

Cited by 6 publications

(1 citation statement)

References 22 publications

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“…The solutions of these two extra transport equations are fed into the Navier-Stokes equations through the eddy viscosity. The development of the k-ε model incorporated constants that are based on experimental measurementsthe constants were chosen to best match experimental results (Nourani et al 2021).…”

Section: Numerical Simulationmentioning

confidence: 99%

Hydraulic characteristics of flow over stepped and chute spillways (case study: Zirdan Dam)

Salmasi

Abraham

2023

Water Supply

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Stepped spillways are suitable and economical options for high-storage dams that require significant energy dissipation, structural adaptation to roller-compacted concrete dams, and spontaneous flow aeration. In this study, a numerical analysis of the hydraulic characteristics for the skimming flow regime of the stepped spillway of Zirdan Dam is carried out. A comparison between the flow characteristics for stepped and smooth spillways is provided. By preparing numerical models of the spillway using the k-ε RNG turbulence model and the multiphase mixture method, a hydraulic analysis of the flow was completed. To verify the performance of the numerical model, field data were collected and used for validation. The results show that the presence of steps along the spillway cause a significant reduction in the length of the boundary layer and faster aeration occurs. In a stepped spillway, the cavitation index is higher than the critical limit along the entire length of the spillway. Thus, the risk of cavitation and destruction is negligible. On the other hand, with a smooth spillway, the possibility of cavitation may occur. This negative effect (negative pressures) occurs 56 m from the crest of the spillway on the downstream side.

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Section: Numerical Simulationmentioning

confidence: 99%

Hydraulic characteristics of flow over stepped and chute spillways (case study: Zirdan Dam)

Salmasi

Abraham

2023

Water Supply

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Discussion of “Abbas, F. M., & Tanaka, N. (2022). Investigation of flow structure with moat acting as a water cushion at the toe of an overflowing levee. Environmental Fluid Mechanics, 22(4), 865–889.”

Zhu,

Zhang,

Yuan

et al. 2024

Environ Fluid Mech

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Boosting ensembles for estimation of discharge coefficient and through flow discharge in broad-crested gabion weirs

et al. 2022

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Gabion weirs are environment-friendly structures widely used for irrigation and drainage network purposes. These structures' hydraulic performance is fundamentally different from solid weirs' due to their porosity and the existence of a through-flow discharge. This paper investigates the reliability and suitability of a number of Machine learning models for estimation of hydraulic performance of gabion weirs. Generally, three different Boosting ensemble models, including Gradient Boosting, XGBoost, and CatBoost, are compared to the well-known Random Forest and a Stacked Regression model, with respect to their accuracy in prediction of the discharge coefficient and through-flow discharge ratio of gabion weirs in free flow conditions. The Bayesian optimization approach is used to fine-tune model hyper-parameters automatically. Recursive feature elimination analysis is also performed to find optimum combination of features for each model. Results indicate that the CatBoost model has outperformed other models in terms of estimating the through flow discharge ratio (Qin/Qt) with R2 = 0.982, while both XGBoost and CatBoost models have shown close performance in terms of estimating the discharge coefficient (Cd) with R2 of CatBoost equal to 0.994 and R2 of XGBoost equal to 0.992. Weakest results were also produced by Decision tree regressor with R2 = 0.821 and 0.865 for estimation of Cd and Qin/Qt values.

show abstract

Effects of different configurations of sloping crests and upstream and downstream ramps on the discharge coefficient for broad-crested weirs

Cited by 6 publications

References 22 publications

Hydraulic characteristics of flow over stepped and chute spillways (case study: Zirdan Dam)

Hydraulic characteristics of flow over stepped and chute spillways (case study: Zirdan Dam)

Discussion of “Abbas, F. M., & Tanaka, N. (2022). Investigation of flow structure with moat acting as a water cushion at the toe of an overflowing levee. Environmental Fluid Mechanics, 22(4), 865–889.”

Boosting ensembles for estimation of discharge coefficient and through flow discharge in broad-crested gabion weirs

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