Resistance of Open-Channel Flow under the Effect of Bending Deformation of Submerged Flexible Vegetation

Li, Yanhong; Xie, Liquan; Su, Tsung-Chow

doi:10.1061/(asce)hy.1943-7900.0001419

Cited by 16 publications

(15 citation statements)

References 27 publications

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“…The experiments were conducted in a 12.4 m long, 0.3 m deep, and B = 0.3 m wide glass flume at the Hydraulics Laboratory of the School of Soil and Water Conservation at Beijing Forestry University, Beijing, China. The channel bed slope S 0 was adjusted to 0.1%, which is reasonable in nature (Li et al, 2018; Tang et al, 2014). A steady and recycled current was generated through a centrifugal pump by flowing water moving from a reservoir to the flume after passing over a weir.…”

Section: Methodsmentioning

confidence: 99%

Drag Coefficient of Emergent Flexible Vegetation in Steady Nonuniform Flow

Zhang

Wang

Cheng

et al. 2020

Water Resources Research

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Flexible vegetation plays key roles in the natural channel and riparian ecology. This paper investigates the drag coefficient Cdf of an emergent flexible vegetation array in a steady nonuniform flow. Laboratory flume tests of five vegetation densities exposed to a constant flow rate were conducted, and the variation in the water surface was accurately measured. The Saint‐Venant equation was applied to explore vegetation hydrodynamics under nonuniform conditions, and a more widely applicable formula for the vegetated drag of nonuniform flow was proposed. Furthermore, the flexible drag coefficient factor αb was used to represent the flexibility and drag reconfiguration, which were explored from the perspective of material mechanics. The results reveal that the calculated values of Cdf exhibit nonmonotonic variation with increasing Reynolds number along the streamwise direction due to the flow nonuniformity. There are two effects of blockage and sheltering in the emergent vegetated patch: The blockage effect increases the drag coefficient, while the sheltering effect—especially at the leading edge and tail of the vegetated patch—reduces the drag of the flexible canopy due to bending deformation. These two effects achieve equilibration in dense flexible canopies. Finally, by relating αb to flexibility through the slenderness Cauchy number CYS, a nonmonotonic pattern can be obtained for each test. A fitting formula was proposed based on αb as a function of CYS. The results presented in this study can potentially support applications related to the plant flexible dams and vegetated filter strips for river ecosystems.

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Section: Methodsmentioning

confidence: 99%

Drag Coefficient of Emergent Flexible Vegetation in Steady Nonuniform Flow

Zhang

Wang

Cheng

et al. 2020

Water Resources Research

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“…The hydraulic behaviour of a single vegetation element that is completely submerged under the flow surface differs from that which is not submerged (Carollo et al, 2005). Thus, most previous efforts specifically focused on the flow regime, flow velocity, and friction coefficient and their relationships with either submerged or unsubmerged vegetation in the main channels (Carollo et al, 2005;Devi and Kumar, 2016;Dong et al, 2018;Kothyari et al, 2009;Li et al, 2018;Pan and Shangguan, 2006;Salman et al, 2012;Termini, 2015;Termini, 2016;Turner and Chanmeesri, 1984;Zhang et al, 2017;Zhao et al, 2016). Earlier experimental work on flexible grass-lined channels in a submerged condition was conducted by the United States Department of Agriculture (USDA) Soil Conservation Service (SCS) (1954).…”

Section: Introductionmentioning

confidence: 99%

Effect of stem cover on hydraulic parameters of overland flow

et al. 2019

Journal of Hydrology

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“…With the increase of slope gradient and flow discharge, the increased range of sediment transport capacity of vegetation slope (46.93%) was greater than that of brown soil slope (33.98%). Different underlying surfaces lead to the change of flow velocity and the Manning coefficient and affect the sediment transport capacity [ 30 – 32 ]. With the increase of vegetation coverage, Reynolds number decreased [ 33 ], and Manning coefficient increased [ 34 – 36 ].…”

Section: Discussionmentioning

confidence: 99%

Prediction of sediment transport capacity based on slope gradients and flow discharge

et al. 2021

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Sediment transport capacity (Tc) is an essential parameter in the establishment of the slope soil erosion model. Slope type is an important crucial factor affecting sediment transport capacity of overland flow, and vegetation can effectively inhibit soil loss. Two new formulae of sediment transport capacity (Tc) are proposed of brown soil slope and vegetation slope in this study and evaluate the influence of slope gradient (S) and flow discharge (Q) on sediment transport capacity of different slope types. Laboratory experiments conducted using four flow discharges (0.35, 0.45, 0.55, and 0.65 L s-1), four slope gradients (3, 6, 9, and 12°), and two kinds of underlying surface (Brown soil slope, Vegetation slope). The soil particle size range is 0.05–0.5mm. The vegetation stems were 2mm in diameter and randomly arranged. The results show that the sediment transport capacity was positively correlated with the flow discharge and slope gradient. The vegetation slope’s average sediment transport capacity is 11.80% higher than the brown soil slope that same discharge and slope gradient conditions. The sensitivity of sediment transport capacity to flow discharge on brown soil slope is higher than that of slope gradient. The sensitivity of sediment transport capacity of vegetation slope to slope gradient is more heightened than flow discharge. The sediment transport capacity was well predicted by discharge and slope gradient on brown soil slope (R2 = 0.982) and vegetation slope (R2 = 0.993). This method is helpful to promote the study of the sediment transport process on overland flow.

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Resistance of Open-Channel Flow under the Effect of Bending Deformation of Submerged Flexible Vegetation

Cited by 16 publications

References 27 publications

Drag Coefficient of Emergent Flexible Vegetation in Steady Nonuniform Flow

Drag Coefficient of Emergent Flexible Vegetation in Steady Nonuniform Flow

Effect of stem cover on hydraulic parameters of overland flow

Prediction of sediment transport capacity based on slope gradients and flow discharge

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