Dam-break flow dynamics over a stepped channel with vegetation

Khoshkonesh, Alireza; Daliri, Mohammad Reza; Riaz, Khuram; Dehrashid, Fariba Ahmadi; Bahmanpouri, Farhad; Francesco, Silvia Di

doi:10.1016/j.jhydrol.2022.128395

Cited by 13 publications

(6 citation statements)

References 47 publications

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“…Furthermore, with the parameter V/v c ≤ 4, a decrease in the trapping capacity of the Lobo River water reservoir is observed. The reduction in the trapping capacity of the water reservoir could be due to the turbulence phenomenon that leads to the resuspension of particles that are expelled downstream of the weir, thus reducing the efficiency of the reservoir [41,42]. According to Sanchez [26] and Schmidt [43], this decrease in the Lobo River reservoir trapping capacity could be due to flocculation and the high variability in the rate of fall of suspended particles in the water column.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the Gamma Law for Settling Velocity and Trapping Capacity Analysis of Suspended Particles in a Dam Reservoir (Lobo River in Côte d’Ivoire)

Koffi

Sanchez

Kouadio

et al. 2023

Water

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Human activities and climate change are currently dominant processes that affect hydrological processes, resulting in alterations in water and sediment flows. Evaluation of the settling velocity of suspended solids is a critical parameter in modelling sediment transport. In this study, we investigated seasonal changes in suspended solids’ settling velocity and trapping capacity in the presence and absence of water turbulence on a dam reservoir. Using key parameters such as flow rate, mean settling velocity (V¯), critical velocity (vc), suspended solids concentration, ratio V¯/vc, and shape parameter ‘r’, the trapping capacity on the dam reservoir on the Lobo River in a tropical region was estimated. The results show that, considering the settling velocity of suspended solids, following the Gamma distribution law remains an innovative solution proposed to evaluate the trapping capacity in water reservoirs. The results show that the mean suspended solids settling velocity V¯ is well above the median rate V50%. For a parameter V¯/vc ≥ 4, there is an increase in the trapping capacity of the water retention. As established, a large proportion of the sediment is trapped. Furthermore, for a parameter V¯/vc ≤ 4, a decrease in the trapping capacity of the Lobo River water reservoir is observed.

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Section: Discussionmentioning

confidence: 99%

Evaluation of the Gamma Law for Settling Velocity and Trapping Capacity Analysis of Suspended Particles in a Dam Reservoir (Lobo River in Côte d’Ivoire)

Koffi

Sanchez

Kouadio

et al. 2023

Water

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“…Additionally, the present results offer benchmark data for future numerical investigations given the increased focus on modeling and simulating dam-break problems 61,[81][82][83][84][85][86] over obstructions and vegetated bed scenarios. [87][88][89][90] The need to move beyond wall friction representation for energy losses is recognized in large scale models but alternatives remain in short supply. 18 Progress on these alternatives using a quadratic drag law is timely given the rapid advancements in water level measurements from space (to within 10 cm) 91 and the wealth of research on drag coefficients for different geometries as derived from steady-uniform flow.…”

Section: Conclusion and Broader Implicationsmentioning

confidence: 99%

The advancing wave front on a sloping channel covered by a rod canopy following an instantaneous dam break

Buono,

Katul,

Poggi

2024

Physics of Fluids

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The drag coefficient Cd for a rigid and uniformly distributed rod canopy covering a sloping channel following the instantaneous collapse of a dam was examined using flume experiments. The measurements included space x and time t high resolution images of the water surface h(x, t) for multiple channel bed slopes So and water depths behind the dam Ho along with drag estimates provided by sequential load cells. Using these data, an analysis of the Saint-Venant equation (SVE) for the front speed was conducted using the diffusive wave approximation. An inferred Cd=0.4 from the h(x, t) data near the advancing front region, also confirmed by load cell measurements, is much reduced relative to its independently measured steady-uniform flow case. This finding suggests that drag reduction mechanisms associated with transients and flow disturbances are more likely to play a dominant role when compared to conventional sheltering or blocking effects on Cd examined in uniform flow. The increased air volume entrained into the advancing wave front region as determined from an inflow–outflow volume balance partly explains the Cd reduction from unity.

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“…In a real dam breach, sediment loads originate from three primary sources: the reservoir, downstream channel substrates, and dam material (Baklanov, 2007;Khoshkonesh et al, 2019Khoshkonesh et al, , 2022. Particularly, the characteristics of the reservoir and downstream substrates play a pivotal role in determining the evolution of waves during a dam failure (Leal et al, 2006;Mei et al, 2022;Xu et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of dam break flow over erodible beds with diverse substrate level variations

Khoshkonesh,

Nsom,

Okhravi

et al. 2024

Journal of Hydrology and Hydromechanics

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This study aimed to comprehensively investigate the influence of substrate level difference and material composition on dam break wave evolution over two different erodible beds. Utilizing the Volume of Fluid (VOF) method, we tracked free surface advection and reproduced wave evolution using experimental data from the literature. For model validation, a comprehensive sensitivity analysis encompassed mesh resolution, turbulence simulation methods, and bed load transport equations. The implementation of Large Eddy Simulation (LES), non-equilibrium sediment flux, and van Rijn’s (1984) bed load formula yielded higher accuracy compared to alternative approaches. The findings emphasize the significant effect of substrate level difference and material composition on dam break morphodynamic characteristics. Decreasing substrate level disparity led to reduced flow velocity, wavefront progression, free surface height, substrate erosion, and other pertinent parameters. Initial air entrapment proved substantial at the wavefront, illustrating pronounced air-water interaction along the bottom interface. The Shields parameter experienced a one-third reduction as substrate level difference quadrupled, with the highest near-bed concentration observed at the wavefront. This research provides fresh insights into the complex interplay of factors governing dam break wave propagation and morphological changes, advancing our comprehension of this intricate phenomenon.

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Dam-break flow dynamics over a stepped channel with vegetation

Cited by 13 publications

References 47 publications

Evaluation of the Gamma Law for Settling Velocity and Trapping Capacity Analysis of Suspended Particles in a Dam Reservoir (Lobo River in Côte d’Ivoire)

Evaluation of the Gamma Law for Settling Velocity and Trapping Capacity Analysis of Suspended Particles in a Dam Reservoir (Lobo River in Côte d’Ivoire)

The advancing wave front on a sloping channel covered by a rod canopy following an instantaneous dam break

Numerical investigation of dam break flow over erodible beds with diverse substrate level variations

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