Impact of dissipation and dispersion terms on simulations of open-channel confluence flow using two-dimensional depth-averaged model

2013 ◽  
Vol 28 (8) ◽  
pp. 3230-3240 ◽  
Author(s):  
Qing-yuan Yang ◽  
Wei-Zhen Lu ◽  
Su-fen Zhou ◽  
Xie-kang Wang
Keyword(s):  
Open Channel ◽  
Two Dimensional ◽  
Dispersion Terms ◽  
Averaged Model ◽  
Channel Confluence

scholarly journals Turbulent flow structure at a 90-degree open channel confluence: Accounting for the distortion of the shear layer

2016 ◽  
Vol 12 ◽  
pp. 130-147 ◽  
Author(s):  
Saiyu Yuan ◽  
Hongwu Tang ◽  
Yang Xiao ◽  
Xuehan Qiu ◽  
Huiming Zhang ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Shear Layer ◽  
Flow Structure ◽  
Open Channel ◽  
Turbulent Flow Structure ◽  
Channel Confluence

Two-dimensional depth-averaged model simulation

2015 ◽  
Author(s):  
Anna Avramenko ◽  
Jari Hamalainen
Keyword(s):  
Model Simulation ◽  
Two Dimensional ◽  
Averaged Model

Application of a two-dimensional hydrodynamic reservoir model to Lake Erie

2001 ◽  
Vol 58 (5) ◽  
pp. 858-869 ◽  
Author(s):  
L Boegman ◽  
M R Loewen ◽  
P F Hamblin ◽  
D A Culver
Keyword(s):  
Lake Erie ◽  
Nutrient Loading ◽  
Thermal Structure ◽  
Domain Model ◽  
Water Level Fluctuations ◽  
Two Dimensional ◽  
Large Lakes ◽  
Physical Forcing ◽  
Model Predictions ◽  
Averaged Model

The relative impacts of changes in nutrient loading and zebra mussel establishment on plankton in large lakes are strongly influenced by hydrodynamics, yet adequately modelling the temporal-spatial complexity of physical and biological processes has been difficult. We adapted a two-dimensional public domain model, CE-QUAL-W2, to test whether it could provide a hydrodynamically accurate simulation of the seasonal variation in the vertical-longitudinal thermal structure of Lake Erie. The physical forcing for the model is derived from surface meteorological buoys and measurements of precipitation, inflows, and outflows. To calibrate and validate the model, predictions were compared with an extensive set of field data collected during May through September 1994. The model accurately predicted water-level fluctuations without adjustment. However, significant modifications to the eddy coefficient turbulence algorithm were required to simulate acceptable longitudinal currents. The thermal structure was accurately predicted in all three basins, even though this laterally averaged model cannot simulate Coriolis effects. We are currently extending the model's water-quality module to include the effects of nutrient loading and zebra mussels on the plankton.

Flow patterns in an open channel confluence with a small ratio of main channel to tributary discharge

2014 ◽  
pp. 989-996 ◽  
Author(s):  
L Schindfessel ◽  
S Creëlle ◽  
T Boelens ◽  
T De Mulder
Keyword(s):  
Open Channel ◽  
Flow Patterns ◽  
Main Channel ◽  
Small Ratio ◽  
Channel Confluence

RIGID-LID LES PREDICTIONS OF THE 3D-FLOW IN AN OPEN-CHANNEL CONFLUENCE WITH CONCORDANT AND DISCORDANT BEDS

2019 ◽  
Author(s):  
PEDRO XAVIER RAMOS ◽  
LAURENT SCHINDFESSEL ◽  
JOÃO PEDRO PÊGO ◽  
TOM DE MULDER
Keyword(s):  
Open Channel ◽  
3D Flow ◽  
Channel Confluence

scholarly journals Impact of initial conditions on the prediction of the spread of thermal pollution in rivers

2018 ◽  
Vol 40 ◽  
pp. 05048
Author(s):  
Monika B. Kalinowska ◽  
Pawel M. Rowiński ◽  
Artur Magnuszewski
Keyword(s):  
Open Channel ◽  
Flow Model ◽  
River Flow ◽  
Initial Conditions ◽  
Two Dimensional ◽  
River Temperature ◽  
Heated Water ◽  
Different Temperatures ◽  
Rivmix Model ◽  
Water Depths

The influence of initial conditions on the prediction of the increase of river temperature below the point of release of heated water for a designed power plant has been analysed in this study. The results for different assumed values of river flow and different temperatures of the discharged heated water have been presented. The results have been analysed taking into account existing legal frames. The two-dimensional inhouse RivMix model has been used to simulate the temperature distribution whereas the two-dimensional depth-averaged turbulent open channel flow model CCHE2D has been used to simulate the velocity fields and the water depths for the selected flows of the river.

scholarly journals Flat vs. curved rigid-lid LES computations of an open-channel confluence

2019 ◽  
Vol 21 (2) ◽  
pp. 318-334 ◽  
Author(s):  
Pedro Xavier Ramos ◽  
Laurent Schindfessel ◽  
João Pedro Pêgo ◽  
Tom De Mulder
Keyword(s):  
Free Surface ◽  
Secondary Flow ◽  
Open Channel ◽  
Pressure Field ◽  
Large Eddy Simulations ◽  
Numerical Treatment ◽  
Mean Flow ◽  
Large Eddy ◽  
Flow Case ◽  
Channel Confluence

Abstract This paper describes the application of four Large Eddy Simulations (LES) to an open-channel confluence flow, making use of a frictionless rigid-lid to treat the free-surface. Three simulations are conducted with a flat rigid-lid, at different elevations. A fourth simulation is carried out with a curved rigid-lid which is a closer approximation to the real free-surface of the flow. The curved rigid-lid is obtained from the time-averaged pressure field on the flat rigid-lid from one of the initial three simulations. The aim is to investigate the limitations of the free-surface treatment by means of a rigid-lid in the simulation of an asymmetric confluence, showing the differences that both approaches produce in terms of mean flow, secondary flow and turbulence. After validation with experimental data, the predictions are used to understand the differences between adopting a flat and a curved rigid-lid onto the confluence hydrodynamics. For the present flow case, although it was characterized by a moderately low downstream Froude number (Fr ≈ 0.37), it was found that an oversimplification of the numerical treatment of the free-surface leads to a decreased accuracy of the predictions of the secondary flow and turbulent kinetic energy.

A new model of shoaling and breaking waves. Part 2. Run-up and two-dimensional waves

2019 ◽  
Vol 867 ◽  
pp. 146-194 ◽  
Author(s):  
G. L. Richard ◽  
A. Duran ◽  
B. Fabrèges
Keyword(s):  
Large Scale ◽  
Turbulent Viscosity ◽  
Breaking Waves ◽  
Small Scale ◽  
Two Dimensional ◽  
Numerical Resolution ◽  
Wide Range ◽  
Scale Turbulence ◽  
Run Up ◽  
Averaged Model

We derive a two-dimensional depth-averaged model for coastal waves with both dispersive and dissipative effects. A tensor quantity called enstrophy models the subdepth large-scale turbulence, including its anisotropic character, and is a source of vorticity of the average flow. The small-scale turbulence is modelled through a turbulent-viscosity hypothesis. This fully nonlinear model has equivalent dispersive properties to the Green–Naghdi equations and is treated, both for the optimization of these properties and for the numerical resolution, with the same techniques which are used for the Green–Naghdi system. The model equations are solved with a discontinuous Galerkin discretization based on a decoupling between the hyperbolic and non-hydrostatic parts of the system. The predictions of the model are compared to experimental data in a wide range of physical conditions. Simulations were run in one-dimensional and two-dimensional cases, including run-up and run-down on beaches, non-trivial topographies, wave trains over a bar or propagation around an island or a reef. A very good agreement is reached in every cases, validating the predictive empirical laws for the parameters of the model. These comparisons confirm the efficiency of the present strategy, highlighting the enstrophy as a robust and reliable tool to describe wave breaking even in a two-dimensional context. Compared with existing depth-averaged models, this approach is numerically robust and adds more physical effects without significant increase in numerical complexity.

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