CFD modeling the flow dynamics in an open channel with double-layered vegetation

Dehrashid, Fariba Ahmadi; Heidari, Mojtaba; Rahimi, Hamidreza; Khoshkonesh, Alireza; Yuan, Saiyu; Tang, Xiaonan; Lu, Chunhui; Wang, Xiang

doi:10.1007/s40808-022-01513-4

Cited by 8 publications

(4 citation statements)

References 32 publications

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“…The growth of bottomland vegetation has been proven to have a significant impact on the resistance of flood channels [26,48]. It can be affected by climate change as well as anthropogenic activities.…”

Section: Bottomland Vegetationmentioning

confidence: 99%

Analysis of Flood Water Level Variation in the Yichang–Chenglingji Reach of the Yangtze River after Three Gorges Project Operation

Jiang,

Zeng

2024

Water

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Since the impoundment of the Three Gorges Project, the downstream hydrology and river dynamics have been modified. The Yichang–Chenglingji Reach (YCR), as a part of the mainstream of the Middle Yangtze River, has consequently been significantly scoured, which has resulted in stream trenching and section enlargements, without showing any obvious trend in flood level variation, however. This phenomenon can be caused by the increase in riverbed resistance due to river geomorphological change and bottomland vegetation development and the backwater effect of Dongting Lake. To investigate how these factors influence the flood water levels, this study analyzed the variations in the influencing factors based on observational data, theoretical analysis and mathematical modelling, including river channel scouring, riverbed resistance, and the influence of Dongting Lake backwater. Then, the impact of these factors on flood levels was evaluated, followed by a comparative analysis of the effects of various factors. The results show that both the flood backwater height (ΔZ) and the backwater influence range (L) are positively correlated with the outflow intensity (T) at the Chenglingji station. The backwater effect decreases gradually with increasing upstream distance, and the influence on the upstream reach can extend up to Shashi city. It was also indicated that the increase in riverbed resistance due to bottomland vegetation development and river geomorphology are dominant factors in inhibiting flood level declines in the YCR, while the backwater of Dongting Lake just affects local regions. This study can provide a better understanding of the flood level changes of the YCR and thus contribute to flood control and riverbank protection of the Yangtze River in the future.

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Section: Bottomland Vegetationmentioning

confidence: 99%

Analysis of Flood Water Level Variation in the Yichang–Chenglingji Reach of the Yangtze River after Three Gorges Project Operation

Jiang,

Zeng

2024

Water

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“…The presence of vegetation reduces the flow velocity profile, Reynolds shear stress, and turbulence intensity, which means that vegetation can be an effective tool for reducing flow resistance. Ahmadi et al [17] used numerical methods to study the effects of inundation conditions, vegetation arrangement, and vegetation density on water flow velocity. The steady-state flow inside plant channels was reproduced using a CFD model.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Influence of Reed Vegetation on the Hydraulic Characteristics of the Huai River Inflow Channel

Zhang,

Cheng,

Zhang

et al. 2024

Water

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When there is vegetation on the beach or main channel bed, it will have a significant impact on the river channel. This study was based on physical model experiments to investigate the flow conditions of the Jinhu section of the Huaihe River estuary, revealing the influence of reed vegetation on water flow resistance. A new comprehensive roughness formula was proposed, and the predictive effectiveness of the formula was verified. The theoretical results indicate that under the condition of vegetation not being submerged, the comprehensive roughness is directly proportional to the square root of vegetation density in areas with vegetation coverage, the square root of water surface vegetation coverage, and the 2/3 power of the hydraulic radius. The bottom slope does not affect it. Under the condition of vegetation inundation, the comprehensive roughness is smaller than that under the condition of no inundation. The experimental prediction results of the influence of reeds on roughness indicate that the measured roughness values and theoretical roughness calculation values are in good agreement. Under the same operating conditions, the roughness gradually decreases with an increase in flow rate. Under the full-reed working condition, the calculated roughness value and the measured roughness value have the same trend of change, both decreasing with the increase in flow rate. The experimental prediction results of the influence of reeds on the relationship between water level and flow rate show that the roughness value of 0 increases with the increase in reed grass surface coverage rate Ki, and an increase in Ki can lead to an increase in comprehensive roughness.

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“…It encompasses various aspects such as the bed material, bed elevation, and bed compaction and mobility. These factors collectively contribute to strengthening the retention forces that act against flood propagation (Dehrashid et al, 2023;Issakhov et al, 2018;Kim et al, 2017;Oguzhan, and Aksoy, 2020;Riaz et al, 2022). Understanding the dynamics of dam failure on vulnerable terrains is of paramount importance.…”

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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CFD modeling the flow dynamics in an open channel with double-layered vegetation

Cited by 8 publications

References 32 publications

Analysis of Flood Water Level Variation in the Yichang–Chenglingji Reach of the Yangtze River after Three Gorges Project Operation

Analysis of Flood Water Level Variation in the Yichang–Chenglingji Reach of the Yangtze River after Three Gorges Project Operation

Investigation of the Influence of Reed Vegetation on the Hydraulic Characteristics of the Huai River Inflow Channel

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

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