scholarly journals Air Pollution Steady-State Advection-Diffusion Equation: The General Three-Dimensional Solution

2012 ◽  
Vol 03 (09) ◽  
pp. 1124-1134 ◽  
Author(s):  
Daniela Buske ◽  
Marco Túllio Vilhena ◽  
Tiziano Tirabassi ◽  
Bardo Bodmann
Keyword(s):  
Air Pollution ◽  
Steady State ◽  
Diffusion Equation ◽  
Three Dimensional ◽  
Dimensional Solution ◽  
Advection Diffusion Equation ◽  
Advection Diffusion

scholarly journals NUMERICAL MODEL OF 3D MORPHODYNAMIC AFTER OFFSHORE NOURISHMENT

2011 ◽  
Vol 1 (32) ◽  
pp. 55 ◽  
Author(s):  
Masamitsu Kuroiwa ◽  
Yoko Shibutani ◽  
Yuhei Matsubara ◽  
Takayuki Kuchiishi ◽  
Mazen Abualtyef
Keyword(s):  
Numerical Model ◽  
Diffusion Equation ◽  
Suspended Sediment Concentration ◽  
Three Dimensional ◽  
Sediment Concentration ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Advection Diffusion Equation ◽  
Advection Diffusion ◽  
Sand Material

A three-dimensional model of morphodynamics after offshore nourishment was developed. In the presented model, the 3D beach evolution model that is not only after nourishment but also taking into account the nourishment process of injected sand material. In order to consider the injected process of sand, the computation using the advection-diffusion equation for suspended sediment concentration was adapted in the model. The presented model was applied to an idealized beach with two groins in order to investigate the performance of the model, and then, the model was applied to a field observation result for shoreface nourishment carried out at the Egmond aan Zee in the Netherlands. Finally, the applicability of the presented model was discussed from the computed results.

An Analytical Methodology to Air Pollution Modelling in Atmosphere

2019 ◽  
Vol 396 ◽  
pp. 91-98 ◽  
Author(s):  
Régis S. Quadros ◽  
Glênio A. Gonçalves ◽  
Daniela Buske ◽  
Guilherme J. Weymar
Keyword(s):  
Analytical Solution ◽  
Diffusion Equation ◽  
Separation Of Variables ◽  
Three Dimensional ◽  
Numerical Inversion ◽  
Analytical Methodology ◽  
Air Pollution Modelling ◽  
Advection Diffusion Equation ◽  
Advection Diffusion ◽  
Using Data

This work presents an analytical solution for the transient three-dimensional advection-diffusion equation to simulate the dispersion of pollutants in the atmosphere. The solution of the advection-diffusion equation is obtained analytically using a combination of the methods of separation of variables and GILTT. The main advantage is that the presented solution avoids a numerical inversion carried out in previous works of the literature, being by this way a totally analytical solution, less than a summation truncation. Initial numerical simulations and statistical comparisons using data from the Copenhagen experiment are presented and prove the good performance of the model.

scholarly journals SOLUÇÃO DA EQUAÇÃO DE ADVECÇÃO-DIFUSÃO TRIDIMENSIONAL PELO MÉTODO GIADMT PARA DOIS TERMOS DE CONTRAGRADIENTE

2016 ◽  
Vol 38 ◽  
pp. 53
Author(s):  
Karine Rui ◽  
Camila Pinto da Costa
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Equation ◽  
Turbulent Flow ◽  
Turbulent Diffusion ◽  
Three Dimensional ◽  
Turbulent Diffusion Coefficient ◽  
Advection Diffusion Equation ◽  
Advection Diffusion

In this work, we present the resolution of the three-dimensional stationary advection-diffusion equation, through the GIADMT technique, considering the nonlocal closure for turbulent flow, using two different parameterization for the countergradient, one proposal by Cuijpers e Holtslag (1998) and another proposed by Roberti et al. (2004). The concentration of pollutants is estimated and compared with the observed data in Copenhagen experiment using different parameterization for the vertical turbulent diffusion coefficient.

A POD-Based Solver for the Advection-Diffusion Equation

2011 ◽  
Author(s):  
Elia Merzari ◽  
W. David Pointer ◽  
Paul Fischer
Keyword(s):  
Diffusion Equation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Galerkin Projection ◽  
Test Problems ◽  
Simulation Code ◽  
Dimensional Flow ◽  
Advection Diffusion Equation ◽  
Advection Diffusion ◽  
Two Dimensional Flow

We present a methodology based on proper orthogonal decomposition (POD). We have implemented the POD-based solver in the large eddy simulation code Nek5000 and used it to solve the advection-diffusion equation for temperature in cases where buoyancy is not present. POD allows for the identification of the most energetic modes of turbulence when applied to a sufficient set of snapshots generated through Nek5000. The Navier-Stokes equations are then reduced to a set of ordinary differential equations by Galerkin projection. The flow field is reconstructed and used to advect the temperature on longer time scales and potentially coarser grids. The methodology is validated and tested on two problems: two-dimensional flow past a cylinder and three-dimensional flow in T-junctions. For the latter case, the benchmark chosen corresponds to the experiments of Hirota et al., who performed particle image velocimetry on the flow in a counterflow T-junction. In both test problems the dynamics of the reduced-order model reproduce well the history of the projected modes when a sufficient number of equations are considered. The dynamics of flow evolution and the interaction of different modes are also studied in detail for the T-junction.

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