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Stress-jump and Continuity Interface Conditions for a Cylinder Embedded in a Porous Medium
, Article Transport in Porous Media ; Volume 107, Issue 1 , 2015 , Pages 171-186 ; 01693913 (ISSN) ; Nouri Borujerdi, A ; Valipour, M. S ; Ellahi, R ; Pop, I ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
The selection of interface boundary conditions between porous-medium and clear-fluid regions is very important for the wide range of engineering applications. In this paper, the difference between two common types of fluid flow interfacial conditions between clear fluid and porous medium is analyzed in detail. These two types of fluid flow interfacial condition are stress-jump and stress-continuity conditions. The effects of porosity on these types of interface condition are studied. The results are presented for different Reynolds numbers in the range 1–40, porosity equal to 0.4 and 0.8 and Darcy number Da=5×10-4. In this study, the Darcy–Brinkmann–Forchheimer model is used to model the...
A computational thermodynamics approach to the Gibbs-Thomson effect
, Article Materials Science and Engineering A ; Volume 443, Issue 1-2 , 2007 , Pages 178-184 ; 09215093 (ISSN) ; Nategh, S ; Sharif University of Technology
2007
Abstract
In two-phase system, curvature of interface leads to increase of solute concentration in matrix. This effect plays a significant role in solidification, precipitation, nucleation and growth and coarsening. There are number of models and formulas for Gibbs-Thomson effect in binary alloys. In this paper with the help of CALPHAD calculations, new approach for describing this effect in binary and multicomponent systems is proposed. In this generalized method no traditional simplifying assumption are considered and this yield to more accurate result for Gibbs-Thomson phenomenon. This model is compared with previous formulas in some case alloying systems. © 2006 Elsevier B.V. All rights reserved
Seepage analysis in multi-domain general anisotropic media by three-dimensional boundary elements
, Article Engineering Analysis with Boundary Elements ; Volume 37, Issue 3 , 2013 , Pages 527-541 ; 09557997 (ISSN) ; Ataie Ashtiani, B ; Sharif University of Technology
2013
Abstract
A three-dimensio111nal boundary element solution for the seepage analysis in multi-domain general anisotropic media has been developed based on the transformation approach. Using analytical eigenvalues and eigenvectors of the hydraulic conductivity tensor, a closed-form coordinate transformation matrix has been provided to transform the quadratic form of governing equation of seepage for the general anisotropic media to the Laplace equation. This transformation allows the analysis to be carried out using any standard BEM codes for the potential theory on the transformed space by adding small pre- and post-processing routines. With this transformation, any physical quantity like the total...