Effects of surface roughness on overflow discharge of embankment weirs

Qian, Shangtuo; Zhang, Yan; Xu, Hui; Wang, Xiaosheng; Feng, Jiangang; Li, Zhixiang

doi:10.1007/s42241-021-0068-y

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…It is very challenging to collect the necessary information for this type of release [25]. Hence, it is crucial to gather pertinent and trustworthy data utilizing experimental settings to explore this phenomenon and test and validate numerical simulations [26,27]. Nevertheless, it was noted that the availability of such data was extremely limited and had drawbacks.…”

Section: Figure 1 Successive Sluice Gate Closures In a Stream Flumementioning

confidence: 99%

Experimental Establishing of Moving Hydraulic Jump in a Trapezoidal Channel

et al. 2023

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This research was prepared as a preliminary laboratory study to achieve a moving hydraulic jump with controlled discharges. It is an initial part of the study that is being prepared to treat the salt tide occurring in the Shatt al-Arab due to the lack of water imports that were coming from the Karun and Karkheh rivers from Iranian territory, as this scarcity caused a salt tide that affected significantly the environmental reality of the city of Basra and the agricultural lands surrounding the Shatt al-Arab, such as the Shatt al-Arab district and the Siba orchards. As part of the proposed solutions, a moving hydraulic jump is created that pushes the salt tongue into the Persian Gulf; the results were promising. A moving hydraulic leap is a good example of unstable super- and sub-critical flow regimes and is regarded as a specific case of unsteady flow in a channel. There aren't many published experiments on this particular flow type, and the quantitative simulation of such a flow state has some inherent complexity. An experimental setup was created for this work in order to assess the hydraulic performance of a moving hydraulic jump in a trapezoidal flume. A sluice gate was installed at the flume's upstream edge to provide an unstable supercritical flow regime, movable hydraulic jumps along the channel, and temporal water stages at the gate's upstream side for the various downstream end boundary situations. Several flow factors, including energy head, pressure head, and flow depth, were estimated from the recorded data. The study found connections between discharge and shifting hydraulic jump variables. By employing relatively stable momentum and energy formulas, simple and time-independent formulas were developed that accurately predicted the pressure head in the subcritical region of an unstable mixed flow. As a result, the moving hydraulic jump factor can be correctly predicted using time-independent correlations by using the discharge variation as a boundary scenario. Doi: 10.28991/CEJ-2023-09-04-08 Full Text: PDF

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Section: Figure 1 Successive Sluice Gate Closures In a Stream Flumementioning

confidence: 99%

Experimental Establishing of Moving Hydraulic Jump in a Trapezoidal Channel

et al. 2023

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“…Both studies (Fritz andHager 1998, Zerihun 2004) analyzed the effects of the relative overflow head on the hydraulic performance of trapezoidal-shaped weirs under free-and submerged-flow conditions. Furthermore, higher-order numerical models were widely applied to explore the submerged-flow characteristics of trapezoidal-and ogee-shaped weirs (e.g., Huang and Ng 2007, Zerihun and Fenton 2007, Pedersen et al 2018, Qian et al 2021. The performance of these types of models has been fine-tuned by using the data of experimental studies that aimed to examine the structure of the flow field (see, e.g., Zerihun 2004, Peltier et al 2018, Biegowski et al 2020, Karim and Mohammed 2020.…”

Section: Introductionmentioning

confidence: 99%

On the Hydraulic Characteristics of Submerged Flow over Trapezoidal-Shaped Weirs

Zerihun¹

2023

Archives of Hydro-Engineering and Environmental Mechanics

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Subcritical flows over highway and railway embankments, commonly encountered during flood events, can be treated like submerged flows over trapezoidal-shaped weirs. In earlier studies, the equation of the submerged-flow discharge for such types of weirs was developed as a function of the degree of submergence and free-flow discharge. However, the application of this equation in practice requires a pre-determined discharge from experiments performed under free-flowconditions. In this study, a discharge equation was deduced from the streamwise momentum balance equation, which overcomes the drawback of the previous approaches. The results of the validation demonstrated that the proposed equation is capable of predicting the submerged-flow discharge of a trapezoidal-shaped weir within ±6.0% of the measured value. Furthermore, the most prominent features of the submerged overflows were examined by systematically analyzing the experimental data. For such flows, the free-surface and bed-pressure profiles are self-similar only over the upstream face of the weir. Results of this investigation confirmed that the degree of submergence and the slope of the downstream weir face significantly affect the characteristics of the submerged flow, but the effect of the latter on the non-modular discharge is marginal.

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“…Jet scours in river beds are a common hydraulic issue in the fields of geomorphology and hydraulic engineering applications (in Figure 1). Insufficient understanding of hydraulic scours and improper treatment may cause destructive actions, such as dam breaks and river bed erosion (Boniforti et al, 2015;Yao and Wu, 2020;Qian et al, 2021). Mason showed the effects of jet aeration and discharge conditions on the final two-dimensional scour and proposed a formula for the scour depth calculations (Manson, 1989).…”

Section: Introductionmentioning

confidence: 99%

Morphology Evolution of Three-Dimensional Scours Under Submerged Jets

2022

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Through physical model tests, the three-dimensional morphological features and their scale changes with time were measured and comparatively analyzed during the scouring of a homogeneous granular bed surface using submerged oblique jets. The effects of various flow velocities and water cushion depths on the depth, length, and width of the scour hole were studied. At the early stage of scour formation, the morphological scales changed more dramatically, and the jet impact flow velocity had a more significant effect on the scour hole relative to the depth of the water cushion; for the final scales in all three directions of the scour, the scour depth developed at a more significant rate relative to the length and width of the scour. The correlation between the depth, length, and width of scour hole formation was achieved based on the time-domain variation pattern of scour hole scales. As the jet velocity increased and the depth of the water cushion decreased, the scour gradually developed from a wide-shallow morphology to a narrow-deep morphology; the impact of three-dimensional morphological features of the scour on hole depth gradually became obvious, appearing to inhibit the development of scour depth. The results of the present experimental tests offered an exploratory study of the effect of three-dimensional morphological features on the formation of jet scours, having constituted the basis for more rational analysis and evaluation of energy dissipation for the hydraulic operation in water conservancy projects.

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Effects of surface roughness on overflow discharge of embankment weirs

Cited by 6 publications

References 17 publications

Experimental Establishing of Moving Hydraulic Jump in a Trapezoidal Channel

Experimental Establishing of Moving Hydraulic Jump in a Trapezoidal Channel

On the Hydraulic Characteristics of Submerged Flow over Trapezoidal-Shaped Weirs

Morphology Evolution of Three-Dimensional Scours Under Submerged Jets

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