A new numerical approach to the solution of PDEs with optimal accuracy on irregular domains and Cartesian meshes—part 2: numerical simulations and comparison with FEM

Radioembolization (RE) is a valuable treatment for liver cancer. It consists of administering radioactive microspheres by an intra-arterially placed catheter with the aim of lodging these microspheres, which are driven by the bloodstream, in the tumoral bed. Even though it is a safe treatment, some radiation-induced complications may arise. In trying to detect or solve the possible incidences that cause nontarget irradiation, simulating the particle- hemodynamics in hepatic arteries during RE by computational fluid dynamics (CFD) tools has become a valuable approach. This paper reviews the parameters that influence the outcome of RE and that have been studied via numerical simulations. In this numerical approach, the outcome of RE is regarded as successful if particles reach the artery branches that feed tumor-bearing liver segments. Up to 10 parameters have been reviewed. The variation of each parameter actually alters the hemodynamic pattern in the vicinities of the catheter tip and locally alters the incorporation of the particles into the bloodstream. Therefore, in general, the local influences of these parameters should result in global differences in terms of particle distribution in the hepatic artery branches. However, it has been observed that under some (qualitatively described) appropriate conditions where particles align with blood streamlines, the local influence resulting from a variation of a given parameter vanishes and no global differences are observed. Furthermore, the increasing number of CFD studies on RE suggests that numerical simulations have become an invaluable research tool in the study of RE.

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Numerical simulation of dispersion of ammonia in industry space using the ANSYS

MATEC Web of Conferences ◽

10.1051/matecconf/201824700044 ◽

2018 ◽

Vol 247 ◽

pp. 00044

Author(s):

Zdzisław Salamonowicz

Keyword(s):

Numerical Simulations ◽

Roughness Parameter ◽

Numerical Approach ◽

Chemical Equipment ◽

Empirical Models ◽

Average Roughness ◽

Danger Zone ◽

Industrial Installation ◽

Heavy Gas ◽

Selection Of

The article presents issues related to numerical simulations of the spread of dangerous substances in the air after emergency release from industrial installation. The work contains the results of numerical simulations of dispersion of ammonia and chlorine after emergency release made by using the ANSYS program, validated based on commonly used models: Gauss and heavy gas. Validation of experimental results based on research and empirical models allowed the selection of boundary parameters and the implementation of dispersion modelling in 3-d space taking into account technical infrastructure. Existing empirical models include terrain obstacles in the form of average roughness parameter, which is shown in general by the range of the danger zone without local topographic conditions. The numerical approach to modelling, in contrast to empirical models, allows to more accurately show the physicochemical phenomena occurring after release in 3-d space, both in the area around the chemical equipment and the buildings along the dangerous substance cloud.

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Estimates Related to the Extended Spectral Control of the Wave Equation

Journal of Mathematics Research ◽

10.5539/jmr.v10n4p156 ◽

2018 ◽

Vol 10 (4) ◽

pp. 156

Author(s):

Cheikh Seck ◽

Abdoulaye Sène ◽

Mary Niane

Keyword(s):

Wave Equation ◽

Numerical Simulations ◽

Numerical Approach ◽

Regular Domain ◽

Spectral Control

In this work, we show through a numerical approach the extended spectral controllability of the wave equation over a portion of a regular domain, and that the spectrum obtained is quasi-symmetrical. Numerical simulations also verify the analytical estimates demonstrated in Niane and al. $[4]$ and the graphic illustrations relating to this spectral controllability were done.

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