Testing Accuracy of Finite Element and Random Walk Schemes in Prediction of Pollutant Dispersion in Coastal Waters

2005 ◽  
Vol 5 (3) ◽  
pp. 199-214 ◽  
Author(s):  
V. Nassehi ◽  
S. Passone
Keyword(s):  
Finite Element ◽  
Random Walk ◽  
Coastal Waters ◽  
Pollutant Dispersion ◽  
Testing Accuracy

Global random walk solvers for fully coupled flow and transport in saturated/unsaturated porous media

2021 ◽  
Author(s):  
Nicolae Suciu ◽  
Davide Illiano ◽  
Alexander Prechtel ◽  
Florin Radu
Keyword(s):  
Finite Element ◽  
Porous Media ◽  
Random Walk ◽  
Transport Processes ◽  
Richards Equation ◽  
Unsaturated Porous Media ◽  
Coupled Flow ◽  
Flow And Transport ◽  
Coupled Flow And Transport ◽  
Fully Coupled

<p>We present new random walk methods to solve flow and transport problems in saturated/unsaturated porous media, including coupled flow and transport processes in soils, heterogeneous systems modeled through random hydraulic conductivity and recharge fields, processes at the field and regional scales. The numerical schemes are based on global random walk algorithms (GRW) which approximate the solution by moving large numbers of computational particles on regular lattices according to specific random walk rules. To cope with the nonlinearity and the degeneracy of the Richards equation and of the coupled system, we implemented the GRW algorithms by employing linearization techniques similar to the <em>L</em>-scheme developed in finite element/volume approaches. The resulting GRW <em>L</em>-schemes converge with the number of iterations and provide numerical solutions that are first-order accurate in time and second-order in space. A remarkable property of the flow and transport GRW solutions is that they are practically free of numerical diffusion. The GRW solvers are validated by comparisons with mixed finite element and finite volume solvers in one- and two-dimensional benchmark problems. They include Richards' equation fully coupled with the advection-diffusion-reaction equation and capture the transition from unsaturated to saturated flow regimes.  For completeness, we also consider decoupled flow and transport model problems for saturated aquifers.</p>

Design and Analysis of a Low-Range Torque Sensor

2013 ◽  
Vol 397-400 ◽  
pp. 1627-1632
Author(s):  
Liang Liang Wang ◽  
Jin Ju Sun ◽  
Qin Mei ◽  
Hao Cai ◽  
Qing Cai Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Model ◽  
Elastic Beam ◽  
Measurement Range ◽  
Torque Sensor ◽  
Beam Structure ◽  
Element Analysis ◽  
Static Calibration ◽  
Testing Accuracy

In order to meet the testing accuracy of torque in the test of biological bone tissue torsion behavior, a strain gauge torque sensor based on multi-beam structure is designed. The mechanical model of the torque sensor is given and the parameters of the elastic beam structure have been optimized by finite element analysis. Finally the material of the structure and processing technology are determined and static calibration is carried out. Experimental results show that the linearity is 0.9% and the sensitivity is 0.14mV/V in the measurement range from 0 to 0.5Nm with 0.3% resolution.

Global Illumination as a Combination of Continuous Random Walk and Finite-Element Based Iteration

2001 ◽  
Vol 20 (3) ◽  
pp. 288-298 ◽  
Author(s):  
Laszlo Szirmay-Kalos ◽  
Ferenc Csonka ◽  
Gyorgy Antal
Keyword(s):  
Finite Element ◽  
Random Walk ◽  
Global Illumination ◽  
Continuous Random Walk

BOUNDARY CONDITIONS IN FINITE ELEMENT MODELING OF STRATIFIED COASTAL CIRCULATION

1988 ◽  
Vol 1 (21) ◽  
pp. 190
Author(s):  
George C. Christodoulou ◽  
George D. Economou
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Coastal Waters ◽  
Stratified Flow ◽  
Element Model ◽  
Numerical Computations ◽  
Element Modeling ◽  
Sponge Layer

The effect of boundary conditions on numerical computations of stratified flow in coastal waters is examined. Clamped, free radiation and sponge layer conditions are implemented in a two-layer finite element model and the results of simple tests in a two-layer stratified basin are presented.

On the modeling of atmospheric pollutant dispersion during a diurnal cycle: A finite element study

2015 ◽  
Vol 118 ◽  
pp. 19-27 ◽  
Author(s):  
Roseane A.S. Albani ◽  
Fernando P. Duda ◽  
Luiz Cláudio G. Pimentel
Keyword(s):  
Finite Element ◽  
Diurnal Cycle ◽  
Pollutant Dispersion ◽  
Atmospheric Pollutant ◽  
Finite Element Study ◽  
Element Study
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