Application of R2S unstructured tetrahedral mesh method to radioactive concrete structure dismantling using AETIUS/FISPACT codes

2020 ◽  
Vol 44 (10) ◽  
pp. 8181-8192
Author(s):  
Jong W. Kim ◽  
Jin Y. Cho ◽  
Young‐Ouk Lee
Keyword(s):  
Concrete Structure ◽  
Tetrahedral Mesh ◽  
Mesh Method ◽  
Unstructured Tetrahedral Mesh

3D borehole-to-surface and surface electromagnetic modeling and inversion in the presence of steel infrastructure

Geophysics ◽  
2020 ◽  
Vol 85 (5) ◽  
pp. E139-E152 ◽  
Author(s):  
Evan Schankee Um ◽  
Jihoon Kim ◽  
Michael Wilt
Keyword(s):  
Em Algorithm ◽  
Computational Cost ◽  
Data Interpretation ◽  
Tetrahedral Mesh ◽  
Dipole Source ◽  
Earth Model ◽  
Electromagnetic Modeling ◽  
Electric Conductor ◽  
Geologic Storage ◽  
Unstructured Tetrahedral Mesh

The borehole-to-surface electromagnetic (EM) method is a viable imaging and monitoring tool for energy reservoirs, geologic storage, geothermal exploration, fault zones, and other subsurface targets. Data interpretation typically requires considering steel-casing effects, but it is difficult and impractical to directly discretize arbitrarily oriented hollow steel-cased wells in a 3D reservoir-scale earth model because of their extremely high electrical conductivity and long hollow geometry. We have considered a borehole-to-surface EM configuration in which an electric dipole source is placed below the bottom of a steel-cased well. To practically simulate the casing effects on EM measurements, we develop a novel 3D finite-element EM algorithm using an unstructured tetrahedral mesh. To avoid excessive use of fine grids for modeling a steel-cased well, the well is replaced with the combination of a short solid conductive prism and a long linewise perfect electric conductor. We find that this combined structure can approximate casing effects at a small fraction of the computational cost required for modeling a complete hollow casing because the linewise structure is volumeless and does not require an excessive number of small elements. We also find that steel-cased wells distant from sources and receivers can be modeled as simple linewise perfect electric conductors, further improving the computational efficiency. Using this approximation, the 3D EM algorithm presented here is well-suited to modeling many arbitrarily oriented steel-cased wells. After verifying the accuracy and efficiency of this approach using various examples, we performed a 3D borehole-to-surface/surface-to-borehole and surface EM inversion and determine that the inversion can image a deep localized target in the presence of steel infrastructure.

scholarly journals Meshing strategy for bifurcation arteries in the context of blood flow simulation accuracy

2019 ◽  
Vol 128 ◽  
pp. 02003 ◽  
Author(s):  
Natalia Lewandowska ◽  
Jędrzej Mosiężny
Keyword(s):  
Real Life ◽  
Flow Simulation ◽  
Numerical Results ◽  
Tetrahedral Mesh ◽  
Shear Stresses ◽  
Simulation Accuracy ◽  
Dimensional Boundary ◽  
Unstructured Tetrahedral Mesh ◽  
Medical University ◽  
Control Surfaces

The study presents a mesh dependency study for a carotid artery bifurcation geometry of a real-life specimen. The results of time-averaged velocity profiles at artery control surfaces and wall shear stresses are compared between a set of structured and unstructured meshes, with varying non–dimensional boundary layer first element thickness (y+) parameter. A set of four meshes in total is considered: a full–hexagonal structured mesh, an unstructured tetrahedral mesh with prism inflation layer, both created for y+=1 and y+=30. Apart from numerical results, overall mesh creation work time, overall analysisstability are compared with the mesh quality results: cell non–orthogonality, cell skew and aspect ratio. Numerical results are validated against results of real–life CT examination performed in Poznań Medical University.

scholarly journals Marine magnetotelluric inversion with an unstructured tetrahedral mesh

2018 ◽  
Vol 214 (2) ◽  
pp. 952-974 ◽  
Author(s):  
Yoshiya Usui ◽  
Takafumi Kasaya ◽  
Yasuo Ogawa ◽  
Hisanori Iwamoto
Keyword(s):  
Tetrahedral Mesh ◽  
Magnetotelluric Inversion ◽  
Unstructured Tetrahedral Mesh

Experimental and numerical aerodynamic analysis of a satellite launch vehicle with strap-on boosters

2004 ◽  
Vol 108 (1085) ◽  
pp. 379-387
Author(s):  
M. Mani ◽  
A. Naghib-Lahouti ◽  
M. Nazarinia
Keyword(s):  
Simple Algorithm ◽  
Aerodynamic Characteristics ◽  
Launch Vehicle ◽  
Base Flow ◽  
Three Dimensions ◽  
Tetrahedral Mesh ◽  
Surface Pressure Distribution ◽  
Satellite Launch Vehicle ◽  
Unstructured Tetrahedral Mesh ◽  
Experimental Values

Abstract Results of numerical simulation of inviscid compressible flow around a generic satellite launch vehicle (SLV) with strap-on boosters using a commercial computational fluid dynamics (CFD) code named Star-CD are experimentally evaluated. Governing equations of flow around the SLV with two and two strap-on boosters were solved in three dimensions using the SIMPLE algorithm in an unstructured tetrahedral mesh, to determine longitudinal aerodynamic coefficients and surface pressure distribution at Mach numbers from 0·6 to 2·0, and angles-of-attack from 0° to 16°. To evaluate the numerical results, 1:100th scale models of the SLV were tested in a trisonic wind tunnel in the same configurations and flow conditions as those analysed numerically. Comparison of results shows reasonable agreement between numerical and experimental values, however, drag coefficients had to be corrected to compensate the effects of base flow and the struts connecting the boosters to the core rocket. This evaluation shows that a relatively simple simulation of flow using a commercial CFD code can be considered an efficient tool for prediction of aerodynamic characteristics of a multi body satellite launch vehicle with a level of accuracy acceptable in the process of preliminary aerodynamic design.

Parallel adaptive mesh-refining scheme on a three-dimensional unstructured tetrahedral mesh and its applications

2006 ◽  
Vol 175 (11-12) ◽  
pp. 721-737 ◽  
Author(s):  
Y.-Y. Lian ◽  
K.-H. Hsu ◽  
Y.-L. Shao ◽  
Y.-M. Lee ◽  
Y.-W. Jeng ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Adaptive Mesh ◽  
Tetrahedral Mesh ◽  
Unstructured Tetrahedral Mesh
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