Study of Scour and Flow Patterns around Triangular-Shaped Spur Dikes

Yarahmadi, Mohammad Bahrami; Pagliara, Stefano; Yabarehpour, Elham; Najafi, Noushin

doi:10.1007/s12205-020-2261-x

Cited by 18 publications

(8 citation statements)

References 27 publications

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“…The highest values in C-2 were due to the corner (edge) of the rectangular shape that faces the high flow. Yarahmdi et al [9] found that the R shape spur has a maximum depth of scour hole at u/s, while for the T shape, it is vice versa. So, it means that the T shape is better compared with R in the case of the depth of scourhole.…”

Section: Depth-averaged Streamwise Velocity Distributionmentioning

confidence: 99%

“…Studying the flow mechanism around different spurs is a very comprehensive and challenging topic in hydraulic engineering. From the past literature review, it can be observed that maximum study was related to the flow mechanism near the spur; however, a few found the best combination of the spur [9]. The permeable and impermeable spur with slope produced minimum turbulent kinetic energy (TKE) and shear stress.…”

Section: Introductionmentioning

confidence: 99%

“…1c. The head shapes may be rectangular [19][20][21][22], circular [23,24], and tri-angular [9,[25][26][27][28]. The motivation for this study is to improve our understanding of flows around dikes combined with different head shapes.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Flow Dynamics Around a Combination of Different Head Shapes of Spur Dikes

2022

Teh. vjesn.

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Spur dikes are widely used as river training structures throughout the globe to improve navigation, strengthen flood protection, and save erodible banks. This study investigates the flow behaviour of multiple spurs using similar and different head shapes instead of adding an extra structure. The novelty of the study lies in finding out the best combination of head shapes among circular (C), rectangular (R), and triangular (T) that can reduce the responsible factors of scouring and erosion. The responsible factors for scour and erosion include high magnitude velocity, pressure, turbulence kinetic energy (TKE), Reynold stresses, and wall shear stresses. Nine combinations (3 same, i.e., CCC, RRR, and TTT and six different, i.e., CRC, CTC, RCR, RTR, TCT, TRT) of spurs were investigated using Computational Fluid Dynamics (CFD) code FLUENT. Firstly, in the analysis of similar head shapes, more reduction in the values of scour and erosion responsible factors were observed in CCC combination (20% in velocity, 45% in pressure, 41% in TKE, and 43% in normal Reynold stresses). Finally, the reduction was further improved in analysing different head shapes. The CTC combination showed the most effective results in reducing the prescribed factors (43% in velocity, 57% in pressure, 51% in TKE, and 54% in normal Reynold stresses) compared to both combinations of head shapes. Therefore, to protect riverbank and spur head failure due to severe turbulent flow, the combination of spurs (CTC) could be preferred.

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Section: Depth-averaged Streamwise Velocity Distributionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of Flow Dynamics Around a Combination of Different Head Shapes of Spur Dikes

2022

Teh. vjesn.

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“…Due to the asymmetric layout, there were significant differences in flow properties between ipsilateral groins and alternate groins. According to previous research [55,56], the extension of the horizontal vortex downstream of a groin can be used as a criterion for selecting the suitable spacing between groins. In spite of all this extensive research, it is still difficult to make a direct estimation of the backflow scope behind groins deployed at both riverbanks.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Backflow Patterns Induced by a Bilateral Groin Pair with Different Spacing

Kuang

Zheng

et al. 2021

Applied Sciences

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Groins are one of the popular manmade structures to modify the hydraulic flow and sediment response in river training. The spacing between groins is a critical consideration to balance the channel-depth and the cost of construction, which is generally determined by the backflow formed downstream from groins. A series of experiments were conducted using Particle Image Velocimetry (PIV) to observe the influence of groin spacing on the backflow pattern of two bilateral groins. The spacing between groins has significant effect on the behavior of the large-scale recirculation cell behind groins. The magnitude of the wake flow induced by a groin was similar to that induced by another groin on the other side, but the flow direction is opposite. The spanwise velocity near the groin tip dictates the recirculation zone width behind the groins due to the strong links between the spanwise velocity and the contraction ratio of channel cross-sections between groins. Based on previous studies and present experimental results, quantitative empirical relationships are proposed to calculate the recirculation zone length behind groins alternately placed at different spacing along riverbanks. This study provides better understanding and a robust formula to assess the backflow extent of alternate groins and identify the optimum groins array configuration.

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“…Some scholars want to protect the river channel through engineering measures to achieve intergenerational equity. Bahrami-Yarahmadi et al study the scour patterns around different spur dikes, trying to direct the flow to the middle of the river to reduce the erosion of the river banks, achieve the balance of ecological habitat protection, protect the river environment and realize sustainable development [ 21 ]. Although intergenerational equity is a key part of the international community’s commitment to the future, there is no uniform strategy to solve water competition between current and future generations.…”

Section: Introductionmentioning

confidence: 99%

Multi-Objective Optimal Allocation of Water Resources Based on the NSGA-2 Algorithm While Considering Intergenerational Equity: A Case Study of the Middle and Upper Reaches of Huaihe River Basin, China

Zhang

Dong

Tian

2020

IJERPH

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With the rapid development of society and the economy, the demand for water resources is increasing. This, combined with the increasing competition for water resources between current and future generations, hinders the sustainable development of society. To alleviate prominent water resources problems, achieve sustainable utilization of water resources and the sustainable development of society and economy, a multi-objective optimal water resources allocation model is proposed, in which different water sources and different water departments are considered to achieve the maximum social and economic benefits of the study area on the premise of water resources sustainability. To meet the needs of future generations, the discount value is introduced to measure intergenerational equity. A case study from seven cities in the upper and middle reaches of the Huaihe River Basin is given to verify the practicality and viability of the model. The non-dominated sorting Genetic Algorithms-2(NSGA-2) was used to find optimal water resources allocation schemes in 2020 and 2050 under the condition of a hydrological drought year (inflow guarantee rate p = 75%). Compared with previous models, the intergenerational equity model considers the sustainability of water resources, has higher social and economic benefits, and ensures the fair distribution of water resources among generations. According to the results, under balanced weight, the water shortage ratio of the seven cities will decrease from 5.24% in 2050 to 1.58% in 2020, and the economic benefit will increase from 79.46(1010CNY) to 168.3(1010CNY), respectively. In addition, the discount value of economic benefit in 2050 is 80.23(1010CNY), which is still higher than that in 2020. This shows that the water resource allocation scheme can eliminate the disparity between supply and demand for water resources and achieve intergenerational equity. Therefore, the intergenerational equity model can alleviate the contradiction of water resources and realize intergenerational equity.

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Study of Scour and Flow Patterns around Triangular-Shaped Spur Dikes

Cited by 18 publications

References 27 publications

Investigation of Flow Dynamics Around a Combination of Different Head Shapes of Spur Dikes

Investigation of Flow Dynamics Around a Combination of Different Head Shapes of Spur Dikes

Experimental Study on Backflow Patterns Induced by a Bilateral Groin Pair with Different Spacing

Multi-Objective Optimal Allocation of Water Resources Based on the NSGA-2 Algorithm While Considering Intergenerational Equity: A Case Study of the Middle and Upper Reaches of Huaihe River Basin, China

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