Numerical simulation of sediment transport in a U-shaped channel with lateral intake: Effects of intake position and diversion angle

2019 ◽  
Vol 30 (09) ◽  
pp. 1950071 ◽  
Author(s):  
Keivan Tavakoli ◽  
Hossien Montaseri ◽  
Pourya Omidvar ◽  
Stefania Evangelista
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Transport Mechanism ◽  
Discrete Phase Model ◽  
Reference Time ◽  
Bed Topography ◽  
Discharge Ratio ◽  
Discrete Phase ◽  
Sediment Particles ◽  
Good Agreement

In this work, the mechanism of sediment transport in a U-shaped channel with a lateral intake is investigated experimentally and numerically, together with the processes of sediment entry into the intake itself and formation of bed topography. Dry sediment is injected into a steady flow in a rigid channel with a bend and sediment particles are traced in time. In order to validate the numerical model, the three components of the flow velocity, as well as the sediment path in time and the diverted sediment ratios, are measured experimentally. A numerical Discrete Phase Model (DPM) is then applied to study the effect of the intake position and diversion angle on the sediment transport mechanism in the bend. The DPM has, in fact, the capability of specifying for each particle its position relative to a reference time and space and, thereby, it is used in this study to analyze the phenomenon evolution and determine the sediment particles diverted into the intake. The comparison between the experimental data and the DPM numerical results shows a good agreement. In order to investigate the mechanism of sediment transport and to evaluate the percentage of the diverted sediments, a parametric study is then conducted through the numerical model, with different positions of the outer bend of the channel, diversion angles of the lateral intake and diversion discharge ratios. The results show that the mechanism of sediment entry into the lateral intake is affected by the diversion discharge ratio. For low discharge ratios, the mechanism of sediment entry to the lateral intake only consists of continuous entrance from the upstream edge of the intake. With the increase of the discharge ratio, it consists of a continuous entrance from the downstream edge and a periodic entrance from the upstream edge of the intake. The DPM results show that, for all diversion discharge ratios, the minimum percentage of sediment entered into the lateral intake corresponds to the position of 120∘ and diversion angle equal to 50∘.

Sediment transport and bed evolution in a 180∘ curved channel with lateral intake: Numerical simulations using Eulerian and Discrete Phase models

2020 ◽  
Vol 31 (08) ◽  
pp. 2050113
Author(s):  
H. Montaseri ◽  
K. Tavakoli ◽  
S. Evangelista ◽  
P. Omidvar
Keyword(s):  
Sediment Transport ◽  
Numerical Simulations ◽  
Numerical Models ◽  
Three Dimensional ◽  
Secondary Flows ◽  
The Other ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Bed Topography ◽  
Discrete Phase

Lateral intakes are hydraulic structures used for domestic, agricultural and industrial water conveyance, characterized by a very complex three-dimensional morphodynamic behavior: since streamlines near the lateral intake are deflected, some vortices form, pressure gradient, shear and centrifugal forces at the intake generate flow separation and a secondary movement, responsible for local scour and sediment deposition. On the other side, the modeling of flows, besides the sediment transport, in curved channels implies some more complications in comparison with straight channels. In this research, this complex process has been investigated experimentally and numerically, with the mechanism of sediment transport, bed topography evolution, flow pattern and their interactions. Experiments were performed in the Laboratory of Tarbiat Modares University, Iran, where a U-shaped channel with a lateral intake was installed and dry sediment was injected at constant rate into a steady flow. Due to the spiral flow, the bed topography changes significantly and the bed forms in turn affect the sediment entering the intake. Different from the previous works on this topic which were mainly based on laboratory experiments, here, Computational Fluid Dynamics (CFD) numerical simulations with FLUENT software were also performed, specifically with the two-phase Eulerian Model (EM) and Discrete Phase Model (DPM), at the aim of evaluating their performance in reproducing the observed physical processes. This software is used for a large variety of CFD problems, but not much for simulating sediment transport phenomena and bed topography evolution. The comparison of the results obtained through the two models against the laboratory experimental data proved a good performance of both the models in reproducing the main features of the flow, for example, the longitudinal and vertical streamlines and the mechanism of particles movement. However, the EM reveals a better performance than DPM in the prediction of the secondary flows and, consequently, of the bed topography evolution, whereas the DPM well depicts the particles pattern, predicts the location of trapped particles and determines the percentage of sediment entering the intake. The numerical models so calibrated and validated were applied to other cases with different positions of the intake in the bend. The results show that mechanism of sediment entrance into the intake varies in different position. If the intake is installed in the second half of the bend, the sediment accumulates along the inner bank of the bend and enters the intake from downstream edge of intake; on the other side, if it is placed in the first half of the bend, the sediment accumulates along both the inner and the outer bends and, therefore, more sediment enters the intake. Also the results of the simulations performed with the DPM model for different positions of the lateral intake show that for all discharge ratios, the position of 120∘ is the one which guarantees the minimum ratio of sediment diverted to the intake (Gr).

Establishment and Validation of a 1-D Numerical Model of Unsteady Flow and Sediment Transport in the Three Gorges Reservoir (TGR)

2013 ◽  
Vol 444-445 ◽  
pp. 901-905
Author(s):  
Ren Yong Huang ◽  
Jie Zhang
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Unsteady Flow ◽  
Calculation Method ◽  
Three Gorges Reservoir ◽  
Three Gorges ◽  
The Three Gorges ◽  
Flow And Sediment Transport ◽  
Simulation Results ◽  
Good Agreement

A numerical model for simulating unsteady flow and sediment transport in the mainstream and its tributaries at the TGR was presented in this paper, and a three-gradation method was applied to solve the flow governing equation. A experience formula was gave for the calculation of the size of groups of different coefficient of saturation recovery based on the analysis, so the traditional calculation method was improved in this paper. The validity of the model was checked with the observed data of the TGR from 2003 to 2011. Good agreement between the calculation and observed data was obtained. The simulation results show that this model could be used to simulate the flow and sediment transport at the TGR.

On Scouring Efficiency of Flush Waves in Sewers: A Numerical and Experimental Study

2019 ◽  
Author(s):  
Maryam Alihosseini ◽  
Paul Uwe Thamsen
Keyword(s):  
Sediment Transport ◽  
Multiphase Model ◽  
Discrete Phase Model ◽  
Sluice Gate ◽  
Ansys Fluent ◽  
Sediment Bed ◽  
Complex Process ◽  
Discrete Phase ◽  
Sand And Gravel ◽  
The Waves

Abstract In sewer sediment management, the removal of depositions using hydraulic flushing gates has recently gotten great attention. Despite numerous investigations, the complex process of sediment transport under flushing waves is not yet well understood. The present work aims to calibrate and validate a coupled computational fluid dynamics and discrete element method (CFD-DEM) to study the fluid-sediment interaction in sewers. The CFD part of the simulation was carried out in the software Ansys Fluent which is two-way coupled to the DEM software EDEM. The multiphase model volume of fluid (VOF) was used to simulate the flushing wave, while the sediments were handled as DEM particles using the discrete phase model (DPM). To validate the 3D model, experimental work has been performed in a circular laboratory pipe with sand and gravel of different size distributions. A construction of a sluice gate was installed to realize the flushing event, which is similar to a dam-break wave. The evolution of the sediment bed and the scouring efficiency of the waves were examined under different flushing conditions. The results showed that the CFD-DEM method could be used to investigate the performance of flushing devices and various features of sediment transport which are not easy to obtain in the laboratory or field.

scholarly journals TRANSPORT OF NILE SAND ALONG THE SOUTHEASTERN MEDITERRANEAN COAST

1984 ◽  
Vol 1 (19) ◽  
pp. 87
Author(s):  
Zev Carmel ◽  
Douglas L. Inman ◽  
Abraham Golik
Keyword(s):  
Sediment Transport ◽  
Transport Mechanism ◽  
Nile Delta ◽  
Mediterranean Coast ◽  
Longshore Sediment Transport ◽  
Transport Path ◽  
Directional Wave ◽  
Wave Induced ◽  
Annual Transport ◽  
Good Agreement

The potential for longshore sediment transport (LST) is estimated from a three-year set of directional wave data measured off Haifa, Israel. The resulting annual cycle of LST, together with an analysis of the wave and shore characteristics, suggests a wave-induced sediment transport mechanism with a uni-directional annual transport that gradually decreases along the transport path from the source (Nile delta) to sink (Haifa Bay). Existing estimates of the rates of transport of Nile sediment are in good agreement with this result.

scholarly journals Modeling of Flocculation and Sedimentation Using Population Balance Equation

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Zhipeng Shi ◽  
Genguang Zhang ◽  
Yuzhuo Zhang ◽  
Tingting He ◽  
Guoliang Pei
Keyword(s):  
Settling Velocity ◽  
Population Balance ◽  
Nonlinear Process ◽  
Fine Sediment ◽  
Population Balance Modeling ◽  
Floc Size ◽  
Bed Topography ◽  
Computational Fluid Dynamics Cfd ◽  
Sediment Particles ◽  
Good Agreement

Flocculation is a special phenomenon for fine sediment or silt in reservoirs and estuaries. Flocculation usually results in changes of size, morphology, and settling velocity of sediment particles and finally changes of bed topography of reservoirs and estuaries. The process of flocculation and sedimentation was simulated based on population balance modeling (PBM) and computational fluid dynamics (CFD); the changes of particle or floc size and their settling velocities over time were examined. The results showed that flocculation is a dynamic and nonlinear process containing aggregation, breakage, reaggregation, and rebreakage between particles, microflocs, and macroflocs. Furthermore, the visual process of flocculation and sedimentation was directly created by the simulation results and is in good agreement with the results of the previous experiments.

A Study of Jet Formation for Premixed Slurry Jet Nozzle Using the Discrete Phase Model

2011 ◽  
Vol 325 ◽  
pp. 638-644 ◽  
Author(s):  
Wu Sheng Luo ◽  
Cheng Yong Wang ◽  
Jun Wang ◽  
Yue Xian Song
Keyword(s):  
Analytical Data ◽  
Phase Model ◽  
Discrete Phase Model ◽  
Jet Formation ◽  
Cfd Simulations ◽  
Cross Sectional ◽  
Discrete Phase ◽  
Pass Through ◽  
Abrasive Suspension ◽  
Good Agreement

Abrasive jets can be used for polishing when fine slurry is used. This paper presents a model for the jet formation process, CFD simulations are carried out for the prediction of flow pattern in a nozzle with abrasive suspension slurry jets using the discrete phase model. The CFD model aids in understanding the process because of the difficulties in performing the direct measurement of the jet axial velocity and radial velocity, the model simulates the different pressure premixed slurry pass through the pipeline and the focus tube to the atmosphere. The model is able to predict the orifice efficiency and the cross sectional profiles of the jet velocity after the nozzle, the modeled results are in good agreement with both experimental and analytical data. The simulation model can be useful in studying the overall slurry jet process and for the optimization of the slurry jet parameters.

Numerical Model of FGD Unit in Power Plant

2014 ◽  
Author(s):  
Armin Silaen ◽  
Bin Wu ◽  
Chenn Q. Zhou ◽  
William Breen
Keyword(s):  
Numerical Model ◽  
Flue Gas ◽  
Flue Gas Desulfurization ◽  
Discrete Phase Model ◽  
Tank Model ◽  
Discrete Phase ◽  
Parametric Studies ◽  
Tower Model ◽  
Model Technique ◽  
So2 Absorption

Numerical model technique was employed to model the reactive multiphase flow inside a flue gas desulfurization (FGD) unit. The model was divided into two parts: (a) the absorption tower model and (b) the reaction tank model. Eulerian-Lagrangian approach was employed in the absorption tower model. Discrete phase model was used to model the limestone slurry droplets and the SO2 absorption by the limestone slurry was included in the model. Eulerian-Eulerian approach was employed in the reaction tank model where the oxidation of the slurry to form gypsum was modeled. The absorption tower model and the reaction tank model are coupled. Parametric studies were performed to investigate the SO2 removal efficiency of the unit.

scholarly journals Discrete Phase Modelling of Sediment Transport and Scouring of Suspended Particles in Dam Spillway

2021 ◽  
Vol 88 (2) ◽  
pp. 38-49
Author(s):  
Nazirul Mubin Zahari ◽  
Mohd Hafiz Zawawi ◽  
Lariyah Mohd Sidek ◽  
Fei Chong Ng ◽  
Mohamad Aizat Abas ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Energy Production ◽  
Particle Image ◽  
Particle Interaction ◽  
Suspended Particles ◽  
Discrete Phase Model ◽  
Dam Management ◽  
Image Velocimetry ◽  
Discrete Phase ◽  
Volume Method

One of foremost issue arise in the dam management and dam reliability assessment is the sedimentation of suspended particles. Sedimentation affected the energy production and efficiency, storage, discharge capacity, and flood attenuation capabilities. In this paper, the sediment transport and scouring in the dam spillway structure was modelled using finite volume method (FVM) based software, ANSYS. The trajectory of suspended particles in the water flow was formulated based on the discrete phase model (DPM). To access the simulation model, particle image velocimetry (PIV) experiment using scaled-down dam spillway model was conducted. The discrepancy between the findings attained from simulation and PIV experiment is less than 4.89%, inferred the numerical model was acceptable. It was found that the maximum scouring rate and maximum deposition rate are respectively 4.20×10−9 kg/s and 2.00×10−6 kg/s. As such, it was empirically approximated the dam maintenance should be scheduled once every 8.9 years, based on sole consideration on resolving the scouring and deposition of suspended particles. This work demonstrated the viability of DPM based numerical simulation in study the fluid-particle interaction of sediment transport problem, particularly for the application of dam reliability.

NUMERICAL MODEL TO SIMULATE THE EROSION ON THE SLOPE DUE TO OVERTOPPING

2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh
Keyword(s):  
Numerical Model ◽  
Flow Model ◽  
Bed Load ◽  
Experiment Data ◽  
Step Method ◽  
Morphological Model ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Finite Difference Method ◽  
Good Agreement

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.

scholarly journals Effects of Blade Parameters on the Flow Field and Classification Performance of the Vertical Roller Mill via Numerical Investigations

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chang Liu ◽  
Zuobing Chen ◽  
Weili Zhang ◽  
Chenggang Yang ◽  
Ya Mao ◽  
...  
Keyword(s):  
Flow Field ◽  
Pressure Difference ◽  
Continuous Phase ◽  
Classification Performance ◽  
Field Analysis ◽  
Discrete Phase Model ◽  
Roller Mill ◽  
Discrete Phase ◽  
Vertical Roller ◽  
Classification Efficiency

The vertical roller mill is an important crushing and grading screening device widely used in many industries. Its classification efficiency and the pressure difference determine the entire producing capacity and power consumption, respectively, which makes them the two key indicators describing the mill performance. Based on the DPM (Discrete Phase Model) and continuous phase coupling model, the flow field characteristics in the vertical roller mill including the velocity and pressure fields and the discrete phase distributions had been analyzed. The influence of blade parameters like the shape, number, and rotating speed on the flow field and classification performance had also been comprehensively explored. The numerical simulations showed that there are vortices in many zones in the mill and the blades are of great significance to the mill performance. The blade IV not only results in high classification efficiency but also reduces effectively the pressure difference in the separator and also the whole machine. The conclusions of the flow field analysis and the blade effects on the classification efficiency and the pressure difference could guide designing and optimizing the equipment structure and the milling process, which is of great importance to obtain better overall performance of the vertical roller mill.

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