A comparative study of longitudinal dispersion models in rigid vegetated compound meandering channels

Farzadkhoo, Maryam; Keshavarzi, Alireza; Hamidifar, Hossein; Javan, Mitra

doi:10.1016/j.jenvman.2018.03.084

Cited by 23 publications

(5 citation statements)

References 62 publications

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“…The flow parameters are shown in Table 1. In previous works (Wood & Liang 1989;Lin & Shiono 1995;Simoes & Wang 1997;Guan 2003;Farzadkhoo et al 2018;Gu et al 2018;Bai & Zeng 2019), the width of floodplain varied from 0.1 m to 2.5 m. Here, the width of the floodplain is 0.1 m, and its height is 10 cm. The width of the main channel is 30 cm.…”

Section: Experiments Setmentioning

confidence: 87%

The streamwise velocity distribution in a two-stage channel with ice cover

Bai

Sun

2021

Water Supply

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The problem of agricultural non-point source pollution has become increasingly serious. How to determine the ecological drainage ditch system is one of the effective methods to solve the agricultural non-point source pollution. This research study focuses on the velocity distribution in a two-stage section ecological channel with ice cover. The results show that the two-stage section channel with ice cover can effectively reduce the flow velocity in the channel and increase the retention time of water in the channel. By comparing with the experimental data, the accuracy of the analytical solution is high, which provides a theoretical reference for the transport of sediment and pollutions in a two-stage section channel with ice cover in the future.

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Section: Experiments Setmentioning

confidence: 87%

The streamwise velocity distribution in a two-stage channel with ice cover

Bai

Sun

2021

Water Supply

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“…The change of x k with different vegetation arrangements, including the regular/irregular arrangements of canopies and the patterns of vegetation communities, has also caught researchers' attentions in recent years. Comparing the residence time in the compound channels with random and tandem arrangement of vegetation in floodplains found that vegetation with tandem arrangement elongates the delay time of the tracer dye, whereas the measurements of the longitudinal dispersion coefficient showed minor differences for conditions with regular and irregular arrangements [87] . However, from the aspect of flow fields, some typical studies showed that irregular arrangement of canopies play an important role in the spatial heterogeneity and thus dispersion [34,88] .…”

Section: Influence Of Vegetation Characteristics On the Longitudinal ...mentioning

confidence: 96%

Longitudinal dispersive coefficient in channels with aquatic vegetation: A review

Yang¹,

Fang²,

Yang³

et al. 2023

J Hydrodyn

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The determination of longitudinal dispersion coefficient in rivers is necessary for pollution control, environmental risk assessment, and management. In rivers with aquatic vegetation, the flow field is remarkably modified by canopies, which affects velocity profiles and dispersion characteristics dominated by the heterogeneity of the velocity field. The dispersion is deduced from lateral and vertical longitudinal velocity gradients for compound channels with vegetated floodplains and rectangular channels with river-wide vegetation, respectively. Although many efforts have been exerted to clarify the dispersion process in different conditions and predict the diffusion of contaminants in vegetated rivers, no studies have introduced it systematically. This study reviews the dispersion coefficient characteristics, including magnitude, main impacted factors, and relationships with flow and vegetation features, in channels with aquatic canopies considering the variation of impact factors changing with the different vegetation and river morphology scenarios. Several typical methodologies for determining longitudinal dispersion coefficients are also summarized to understand the dispersion processes and concepts. Apart from the pioneer outcomes of previous studies, the review also emphasizes the deficiency of existing studies and suggests possible future directions for improving the theory of dispersion in vegetated channels.

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“…They concluded that the magnitude of LDC had an increasing trend by implanting vegetation over the floodplain as well as increasing the relative flow depth. Outcomes of two studies by Farzadkhoo et al 2018Farzadkhoo et al , 2019a indicated that roughening the floodplain with stems was one of the important factors in increasing the longitudinal flow velocity and the Reynolds shear stress in the main channel. The maximum value of nondimension (LDC/U ⁎ H) was also found at the bend apex.…”

Section: State Of the Artmentioning

confidence: 99%

Reliability-based design and implementation of crow search algorithm for longitudinal dispersion coefficient estimation in rivers

Ghaemi

Zhian

Pirzadeh

et al. 2021

Environ Sci Pollut Res

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The longitudinal dispersion coefficient (LDC) of river pollutants is considered as one of the prominent water quality parameters. In this regard, numerous research studies have been conducted in recent years, and various equations have been extracted based on hydrodynamic and geometric elements. LDC’s estimated values obtained using different equations reveal a significant uncertainty due to this phenomenon’s complexity. In the present study, the crow search algorithm (CSA) is applied to increase the equation’s precision by employing evolutionary polynomial regression (EPR) to model an extensive amount of geometrical and hydraulic data. The results indicate that the CSA improves the performance of EPR in terms of R2 (0.8), Willmott’s index of agreement (0.93), Nash–Sutcliffe efficiency (0.77), and overall index (0.84). In addition, the reliability analysis of the proposed equation (i.e., CSA) reduced the failure probability (Pf) when the value of the failure state containing 50 to 600 m2/s is increasing for the Pf determination using the Monte Carlo simulation. The best-fitted function for correct failure probability prediction was the power with R2 = 0.98 compared with linear and exponential functions.

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A comparative study of longitudinal dispersion models in rigid vegetated compound meandering channels

Cited by 23 publications

References 62 publications

The streamwise velocity distribution in a two-stage channel with ice cover

The streamwise velocity distribution in a two-stage channel with ice cover

Longitudinal dispersive coefficient in channels with aquatic vegetation: A review

Reliability-based design and implementation of crow search algorithm for longitudinal dispersion coefficient estimation in rivers

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