Flow over embankment gabion weirs in free flow conditions

Biabani, Roya; Salmasi, Farzin; Nouri, Meysam; Abraham, John

doi:10.1016/j.jher.2022.08.001

Cited by 6 publications

(3 citation statements)

References 23 publications

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“…For an incompressible flow with a constant viscosity, the governing Navier-Stokes equations are written in the form of Equations ( 1) and (2), respectively (Biabani et al 2022). Water Supply Vol 00 No 0, 4…”

Section: Flow Equationsmentioning

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: Flow Equationsmentioning

confidence: 99%

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

Salmasi

Abraham

2023

Water Supply

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“…These can be divided into two general categories: 1) most of them investigated the weirs' hydraulic performance (Salmasi and Sattari 2017;Salmasi et al 2021;Biabani et al 2022;Shariq et al 2022), and 2) the second category studied the flow pattern around these structures (Leu et al 2008;Mohammadpour et al 2013;Fathi-et al 2018;Safarzadeh and Mohajeri 2018;Biabani et al 2022). Studies related to hydraulic performance can be divided into two types of weirs: through flow (Michioku et al 2005;Shariq et al 2020) and simultaneous through and overflow.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Hydraulic Performance of Porous Broad-Crested Weirs with Sloping Crests

Doustkam,

Rahmanshahi,

Fathi-Moghadam

et al. 2024

Water Resour Manage

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Due to the high technical and hydraulic performance and negligible environmental adverse impact of a porous weir, this structure is a reasonable substitute for conventional impermeable solid weirs in water transmission and distribution systems. This research focused on the hydraulic performance of porous broad-crested weirs (PBCWs) with sloping crests. To this end, 30 PBCWs models in free and submerged flow conditions were designed and examined under different operation conditions. In particular, a comparative study was performed between PBCWs with and without sloping crests, the performance of which were then compared with a solid broad-crested weir (SBCW) model. Based on the results and analysis, the PBCWs with sloping crests have a more significant discharge coefficient than common PBCWs (without sloping crests), and the upstream slope has a more significant impact on the discharge coefficient than the downstream slope. In addition, the PBCWs with sloping crests are more sensitive to tailwater than common PBCWs, and thus the discharge reduction factor of the weir with the upstream crest slope is lower than that of the downstream. Finally, based on the extensive experimental results, both nonlinear multivariable regression and gene-expression programming approaches were applied to extract empirical equations for expressing the free flow discharge coefficient and submerged flow discharge reduction factor.

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“…Recently, there have been various investigations concerning porous weirs, both through experiments and numerical simulations based on computational fluid dynamics. These studies can be grouped into two main categories: 1) most of them have focused on analyzing the hydraulic performance of the weirs (Fritz and Hager 1998;Ferreira 2002;Azimi et al 2014;Salmasi and Sattari 2017;Felder and Islam 2017;Abhash and Pandey 2021;Biabani et al 2022), and 2) the second category has examined the flow patterns around them (Leu et al 2008;Mohammadpour et al 2013;Safarzadeh and Mohajeri 2018;Fathi-moghaddam et al 2018;Biabani et al 2022). The studies on hydraulic performance can be further divided into two types of weirs: those that allow flow solely through them (Michioku et al 2005;Shariq et al 2020) and those that permit both through flow and overflow (Salmasi and Sattari 2017;Safarzadeh and Mohajeri 2018;Shariq et al 2022;Hasanian Shirvan et al 2023).…”

Section: Introductionmentioning

confidence: 99%

Multi-approach assessment for predicting submerged discharge reduction factor in porous broad-crested weirs

Seif,

Arman,

Rahmanshahi

2024

Preprint

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Environmentally friendly porous weirs have attracted the attention of researchers and engineers due to their favorable characteristics, surpassing solid weirs in terms of environmental impact, hydraulic performance, and stability. However, accurately estimating the submerged discharge coefficient for porous weirs is challenging due to the complex flow mechanisms involved, particularly under submerged conditions. The discharge under submerged conditions is typically expressed as a multiple of the free flow discharge, along with a coefficient representing the submerged discharge reduction factor (SDRF). This study aims to propose a novel artificial intelligence framework that incorporates metaheuristic techniques to predict SDRF for porous broad-crested weirs (PBCWs). The research utilized generalized normal distribution optimization (GNDO) to optimize the multilayer perceptron (MLP) model, enabling more precise predictions. The performance of the hybrid MLP-GNDO model was compared to that of an MLP, gene-expression programming (GEP), and standard nonlinear regression (SNR) models. A dataset comprising 966 observed experiments was employed to evaluate the proposed models. The results demonstrated that the hybrid MLP-GNDO model outperformed the MLP, GEP, and SR models, achieving a root mean square error of 0.021 and 0.022 and an R2 value of 0.964 and 0.954 for the training and test datasets, respectively. This model accurately predicted the train and test datasets with an average error rate of less than 2%. Regarding accuracy, the models ranked in the following order: MLP, GEP, and SNR.

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Flow over embankment gabion weirs in free flow conditions

Cited by 6 publications

References 23 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)

Experimental Study on the Hydraulic Performance of Porous Broad-Crested Weirs with Sloping Crests

Multi-approach assessment for predicting submerged discharge reduction factor in porous broad-crested weirs

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