SIMULATION OF COASTAL INLET PROCESSES BY ADVECTION-DIFFUSION TRANSPORT MODEL

This paper, the second of a series, presents the results of a numerical study of the advection–diffusion water mixing process between the Havre aux Basques lagoon and the Gulf of St. Lawrence, after the proposed reopening of the lagoon. In this study, the reopening scheme of the inlet, which has been closed in 1957, is analyzed by using a horizontal two-dimensional numerical model. The transport model is based on the Douglas–Wang finite element formulation for a space discretization. The approximation is quadratic, using six-node triangular elements. The semi-implicit Crank–Nicholson scheme is used for a time discretization. The results show that after reopening the lagoon, mixing may take between 5 and 22 days for a diffusion coefficient considered constant throughout the region and varying from 5 to 500 m2/s. Key words: lagoon, Havre aux Basques, advection–diffusion, mixing, numerical model, finite element, Douglas–Wang.

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Discrete Particle Distribution Model for Advection-Diffusion Transport

Journal of Hydraulic Engineering ◽

10.1061/(asce)0733-9429(2001)127:11(980) ◽

2001 ◽

Vol 127 (11) ◽

pp. 980-981 ◽

Cited By ~ 1

Author(s):

Wang Dian-chang ◽

Wang Xing-kui ◽

Yu Ming-zhong ◽

Li Dan-xun ◽

Manuel Costa ◽

...

Keyword(s):

Particle Distribution ◽

Distribution Model ◽

Discrete Particle ◽

Diffusion Transport ◽

Advection Diffusion

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Dynamic identification of boundary conditions for convection-diffusion transport model in the case of noisy measurements

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva ◽

10.15507/2079-6900.21.201904.469-479 ◽

2019 ◽

Vol 21 (4) ◽

pp. 469-479

Author(s):

Anastasia N. Kuvshinova

Keyword(s):

Boundary Conditions ◽

Transport Model ◽

Mixed Boundary ◽

Mixed Boundary Conditions ◽

Simultaneous Estimation ◽

Dynamic Identification ◽

Diffusion Transport ◽

One Dimensional ◽

Convection Diffusion ◽

Noisy Measurements

The paper addresses the problem of dynamic identification of mixed boundary conditions for one-dimensional convection-diffusion transport model based on noisy measurements of the function of interest. Using finite difference method the original model with the partial differential equation is replaced with the discrete linear dynamic system with noisy multisensor measurements in which boundary conditions are included as unknown input vector. To solve the problem, the algorithm of simultaneous estimation of the state and input vectors is used. The results of numerical experiments are presented which confirm the practical applicability of the proposed method.

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3 Dimensional Modeling of Advection-Diffusion Equation

10.31237/osf.io/6wbgh ◽

2019 ◽

Author(s):

Amin Ilia

Keyword(s):

Sediment Transport ◽

Suspended Sediment ◽

Transport Model ◽

Three Dimensional ◽

Water Levels ◽

Dynamics Simulation ◽

Advection Diffusion ◽

Sediment Transport Model ◽

Time Splitting ◽

2D Model

Estimation of flows and sediment transport is challenging as many complexes and interacting physical phenomena need to be accounted for. In this research, a coupled two-dimensional finite volume flow model and a three-dimensional sediment transport model were developed in Fortran. In this model, the depth-integrated current vectors and water level were computed by 2D shallow water equations as the 2D model is computationally much faster than the 3D model. The depth-integrated current vectors were distributed in depths using a logarithmic current distribution equation, log of the wall. These distributed velocities and simulated water levels were used for three-dimensional sediment transport model which is generated using the same scheme. A 3D sediment transport model was preferred over a 2D model as 3D sediment model can estimate vertically diffusion of sediment mass from bedload to suspended sediment load which significantly improves the prediction of morphology evolutions.In order to discretize each subset of equations with the best-suited method, I utilized a time-splitting technique. As a result, I applied the second-order Fromm scheme which was found the best method for solving advection terms and semi-implicit forward time central space method which was found the best method for solving diffusion terms. The time-splitting scheme also reduced the complicity, therefore, the solution became simple and attractive to apply. For developing the sediment transport model, I applied this advection-diffusion concept to estimate the distribution of suspended sediment concentration and the Van Rijn (1981) scheme for the estimation of bedload sediment transport. As it’s very important to estimate and predict this phenomenon accurately, I compared the model with a lab trench experiment and the model results were in agreement with lab experiments. It was shown that the model could accurately simulate sedimentation on the downsloping (deceleration) section and erosion on the upsloping (acceleration) section of a marine trench. This would cause lateral movement of the channel toward the current direction. Being capable of accurate sediment transport and morphological dynamics simulation in this complex setting, this model is validated to be applied to other marine problems.

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Development of an Advection-diffusion Model Using Depth-integrated Equations Based on GPU Acceleration

Korean Society of Hazard Mitigation ◽

10.9798/kosham.2021.21.1.281 ◽

2021 ◽

Vol 21 (1) ◽

pp. 281-289

Author(s):

Sooncheol Hwang ◽

Sangyoung Son

Keyword(s):

Finite Difference ◽

Finite Volume ◽

Transport Model ◽

Finite Difference Methods ◽

Scalar Transport ◽

Gpu Acceleration ◽

Advection Diffusion Equation ◽

Benchmark Tests ◽

Advection Diffusion ◽

Proposed Model

A scalar transport model is developed by adding a depth-averaged advection-diffusion equation to Celeris Advent, which is a Boussinesq-type numerical model that utilizes GPU acceleration. The hybrid finite volume-finite difference method is used to guarantee numerical stability along with the high accuracy of the Boussinesq equation. The advective and diffusive terms are numerically discretized using the finite volume and finite difference methods, respectively. Results of a one-dimensional scalar advection benchmark test showed that the scalar advection by the proposed model was very close to the analytical solution without any remarkable numerical diffusion. In addition, two benchmark tests using experimental data from different hydraulic experiments were numerically reproduced, and the computed results and observed data for scalar transport were found to be in good agreement. The developed model is expected to contribute to real-time disaster prediction for contaminant spills and can assist in preparing countermeasures for these types of disasters.

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