Computational investigation of hydraulic performance variation with geometry in gabion stepped spillways

Reeve, Dominic E.; Zuhaira, Ali Adel; Karunarathna, Harshinie

doi:10.1016/j.wse.2019.04.002

Cited by 20 publications

(14 citation statements)

References 16 publications

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“…As can be seen from Figure (12), some cases do not follow a clear trend due to the undulating free surface or the humps of water that can be observed over the gabion due to the seepage flow inside the porous media. The spillways' geometry could influence seepage flow, therefore that effect could accelerate the intersection between the free surface and the turbulent boundary layer or it could delay it depending on the circumstances.…”

Section: Fig 12 Computational Results Of the Free Surface Aeration Lo...mentioning

confidence: 99%

“…Lin and Xu [25] demonstrated the capability of NEWFLUME by performing a detailed analysis of different case studies involving several turbulent free-surface flows. The numerical model using NEWFLUME was validated against a set of experimental data for gabion stepped spillways by Zuhaira et al [26] and Reeve et al [12]. According to Reeve et al [12], the values of gravel porosity and gravel diameter size used in the experiments should be reflected in the numerical model to achieve a reasonable agreement with experimental data.…”

Section: Numerical Modelling Approachmentioning

confidence: 99%

“…To estimate the non-aerated zone length and the inception point location, non-linear multiple regression equations have been developed for uniform normal stepped spillways by several researchers, including Chanson [34]; Meireles and Matos [20] and Hunt and Kadavy [35], in addition to uniform GSS explored by Reeve et al [12]. None of the previous studies have considered the effect of the step height non-uniformity for GSS on the performance, therefore the present study's computational results were used to derive a new empirical equation to determine the non-aerated zone length for non-uniform GSS.…”

Section: Non-linear Multiple Regression Approach (Nmr)mentioning

confidence: 99%

“…11. In developing Eq.11 for nonuniform GSS, the equation proposed by Reeve et al [12] (Eq. 12) for uniform GSS has been used as a basis.…”

Section: Non-linear Multiple Regression Approach (Nmr)mentioning

confidence: 99%

“…For instance, the design of GSS, energy dissipation over the gabion steps and the seepage interactions with a free-surface flow are discussed and reviewed by Chanson [1]. Reeve et al [12] explored GSS numerically with various step layouts (i.e. normal, inclined, overlapping and pooled steps).…”

Section: Introduction and Overviewmentioning

confidence: 99%

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Numerical investigation of skimming flow characteristics over non-uniform gabion-stepped spillways

Zuhaira

Al‐Hamd

Alzabeebee

et al. 2021

Innov. Infrastruct. Solut.

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Stepped spillways can be defined as human-made hydraulic structures constructed to monitor and control flow release and attain high energy dissipation. Such spillways are commonly used in embankment dams, however it is important that a sufficient chute length is provided to develop the required aerated flow, the point at which this occurs is known as the inception point. This paper focusses on the influence of the non-uniform geometry of gabion stepped spillways (GSS) on the inception point. A numerical investigation using the Reynolds Averaged Navier Stokes (RANS) approach with the software NEWFLUME was adopted to examine the flow over the GSS. The inception point location suggested by the numerical models was compared to the location predicated in the existing formulae available the literature. The data from the model was then used to generate two novel empirical equations.The equations were based on non-linear multiple regression (NMR) and evolutionary polynomial regression (EPR) approaches to deliver improved results for non-uniform gabion stepped spillways. The developed EPR correlation respectively scored R 2 (determination coefficient) and MAE (Mean Absolute Error) values of 0.93 and 1.66 for the training data and 0.83 and 2.7 for the testing data. In the NMR approach, a reduced R 2 value of 0.91 was obtained.The outcomes of this study revealed that the numerical model proposed was able to capture the flow characteristics over the GSS accurately. Additionally, the empirical equations developed in the current investigation yielded better predictions of the inception point location compared to existing equations. Consequently, the findings of this study can be used to improve the future design of GSS. Article Highlights• A validated RANS-based numerical code adopted to model flow over the spillways • The impact of non-uniform geometry of gabion stepped spillways on the non-aerated zone explored• Empirical equations developed with an improved level of accuracy over current equations for prediction of inception point

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Section: Fig 12 Computational Results Of the Free Surface Aeration Lo...mentioning

confidence: 99%