The vertical distribution of suspended sediment and phosphorus in a channel with ice cover

2021 ◽  
Author(s):  
Yu Bai ◽  
Yonggang Duan
Keyword(s):  
Vertical Distribution ◽  
Suspended Sediment ◽  
Ice Cover ◽  
The Vertical Distribution

scholarly journals Fractal derivative model for the transport of the suspended sediment in unsteady flows

2018 ◽  
Vol 22 (Suppl. 1) ◽  
pp. 109-115 ◽  
Author(s):  
Shiqian Nie ◽  
Hong Sun ◽  
Xiaoting Liu ◽  
Wang Ze ◽  
Mingzhao Xie
Keyword(s):  
Vertical Distribution ◽  
Unsteady Flow ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Spatial Location ◽  
Sediment Concentration ◽  
Equation Model ◽  
Advection Dispersion ◽  
Fractal Derivative ◽  
The Vertical Distribution

This paper makes an attempt to develop a Hausdorff fractal derivative model for describing the vertical distribution of suspended sediment in unsteady flow. The index of Hausdorff fractal derivative depends on the spatial location and the temporal moment in sediment transport. We also derive the approximate solution of the Hausdorff fractal derivative advection-dispersion equation model for the suspended sediment concentration distribution, to simulate the dynamics procedure of suspended concentration. Numerical simulation results verify that the Hausdorff fractal derivative model provides a good agreement with the experimental data, which implies that the Hausdorff fractal derivative model can serve as a candidate to describe the vertical distribution of suspended sediment concentration in unsteady flow.

scholarly journals Theoretical Model of Suspended Sediment Concentration in a Flow with Submerged Vegetation

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1656 ◽  
Author(s):  
Da Li ◽  
Zhonghua Yang ◽  
Zhaohua Sun ◽  
Wenxin Huai ◽  
Jianhua Liu
Keyword(s):  
Vertical Distribution ◽  
Suspended Sediment ◽  
Schmidt Number ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Submerged Vegetation ◽  
Distribution Profile ◽  
Turbulent Schmidt Number ◽  
Rouse Number ◽  
The Vertical Distribution

Vegetation in natural river interacts with river flow and sediment transport. This paper proposes a two-layer theoretical model based on diffusion theory for predicting the vertical distribution of suspended sediment concentration in a flow with submerged vegetation. The suspended sediment concentration distribution formula is derived based on the sediment and momentum diffusion coefficients through the inverse of turbulent Schmidt number ( S c t ) or the parameter η which is defined by the ratio of sediment diffusion coefficient to momentum diffusion coefficient. The predicted profile of suspended sediment concentration moderately agrees with the experimental data. Sensitivity analyses are performed to elucidate how the vertical distribution profile responds to different canopy densities, hydraulic conditions and turbulent Schmidt number. Dense vegetation renders the vertical distribution profile uneven and captures sediment particles into the vegetation layer. For a given canopy density, the vertical distribution profile is affected by the Rouse number, which determines the uniformity of the sediment on the vertical line. A high Rouse number corresponds to an uneven vertical distribution profile.

scholarly journals Analytical Models of Velocity, Reynolds Stress and Turbulence Intensity in Ice-Covered Channels

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1107
Author(s):  
Jiao Zhang ◽  
Wen Wang ◽  
Zhanbin Li ◽  
Qian Li ◽  
Ya Zhong ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Reynolds Stress ◽  
Turbulence Intensity ◽  
Vertical Profile ◽  
Open Channel ◽  
Longitudinal Velocity ◽  
Analytical Formula ◽  
Ice Cover ◽  
Analytical Models ◽  
The Vertical Distribution

Ice cover in an open channel can influence the flow structure, such as the flow velocity, Reynolds stress and turbulence intensity. This study analyzes the vertical distributions of velocity, Reynolds stress and turbulence intensity in fully and partially ice-covered channels by theoretical methods and laboratory experiments. According to the experimental data, the vertical profile of longitudinal velocities follows an approximately symmetry form. Different from the open channel flow, the maximum value of longitudinal velocity occurs near the middle of the water depth, which is close to the channel bed with a smoother boundary roughness compared to the ice cover. The measured Reynolds stress has a linear distribution along the vertical axis, and the vertical distribution of measured turbulence intensity follows an exponential law. Theoretically, a two-power-law function is presented to obtain the analytical formula of the longitudinal velocity. In addition, the vertical profile of Reynolds stress is obtained by the simplified momentum equation and the vertical profile of turbulence intensity is investigated by an improved exponential model. The predicted data from the analytical models agree well with the experimental ones, thereby confirming that the analytical models are feasible to predict the vertical distribution of velocity, Reynolds stress and turbulence intensity in ice-covered channels. The proposed models can offer an important theoretical reference for future study about the sediment transport and contaminant dispersion in ice-covered channels.

scholarly journals THE BOTTLENECK PROBLEM FOR TURBULENCE IN RELATION TO SUSPENDED SEDIMENT IN THE SURF ZONE

1986 ◽  
Vol 1 (20) ◽  
pp. 90
Author(s):  
Peter Justensen ◽  
Jorgen Fredsoe ◽  
Rolf Deigaard
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Energy Level ◽  
Vertical Distribution ◽  
Turbulent Kinetic Energy ◽  
Suspended Sediment ◽  
Turbulence Model ◽  
Surf Zone ◽  
Wave Boundary ◽  
The Vertical Distribution

In the present paper the vertical distribution of turbulent kinetic energy k under broken waves is calculated by application of a one-equation turbulence model. The contributions to the energy level originate partly from the production in the wave boundary layer, partly from the production in the roller. Further on, the findings for k are used to calculate the vertical distribution of suspended sediment in broken waves.

scholarly journals Vertical Distribution of Suspended Sediment under Steady Flow: Existing Theories and Fractional Derivative Model

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Shiqian Nie ◽  
HongGuang Sun ◽  
Yong Zhang ◽  
Dong Chen ◽  
Wen Chen ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Turbulent Flow ◽  
Fractional Derivative ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Advection Diffusion Equation ◽  
The Vertical Distribution ◽  
Sediment Settling ◽  
Derivative Order

The fractional advection-diffusion equation (fADE) model is a new approach to describe the vertical distribution of suspended sediment concentration in steady turbulent flow. However, the advantages and parameter definition of the fADE model in describing the sediment suspension distribution are still unclear. To address this knowledge gap, this study first reviews seven models, including the fADE model, for the vertical distribution of suspended sediment concentration in steady turbulent flow. The fADE model, among others, describes both Fickian and non-Fickian diffusive characteristics of suspended sediment, while the other six models assume that the vertical diffusion of suspended sediment follows Fick’s first law. Second, this study explores the sensitivity of the fractional index of the fADE model to the variation of particle sizes and sediment settling velocities, based on experimental data collected from the literatures. Finally, empirical formulas are developed to relate the fractional derivative order to particle size and sediment settling velocity. These formulas offer river engineers a substitutive way to estimate the fractional derivative order in the fADE model.

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