Analysis of equations in the phase-field model
Computational studies of anisotropic diffuse interface model of microstructure formation in solidification
Geothermal flow in porous media
Some applications of parabolic differential equations of Allen-Cahn type in image processing
Homogenization of the transport equation describing convection-diffusion processes in a material with fine periodic structure
In the present contribution we discuss mathematical homogenization and numerical solution of the elliptic problem describing convection-diffusion processes in a material with fine periodic structure. Transport processes such as heat conduction or transport of contaminants through porous media are typically associated with convection-diffusion equations. It is well known that the application of the classical Galerkin finite element method is inappropriate in this case since the discrete solution...
Mathematical modeling of hygro-thermal processes in deformed porous media
In this contribution we propose a model of coupled heat and moisture transport in variable saturated deformed porous media. Solution of this model provides temperature, moisture content and strain as a function of space and time. We present the detailed description of the model and a~numerical illustrative example.
An asynchronous three-field domain decomposition method for first-order evolution problems
We present an asynchronous multi-domain time integration algorithm with a dual domain decomposition method for the initial boundary-value problems for a parabolic equation. For efficient parallel computing, we apply the three-field domain decomposition method with local Lagrange multipliers to ensure the continuity of the primary unknowns at the interface between subdomains. The implicit method for time discretization and the multi-domain spatial decomposition enable us to use different time steps...
Numerical analysis of mathematical model of heat and moisture transport in concrete at high temperatures
In this paper, we present a nonlinear mathematical model for numerical analysis of the behaviour of concrete subject to transient heating according to the standard ISO fire curve. This example allows us to analyse and better understand physical phenomena taking place in heated concrete (thermal spalling).
Coupled heat transport and Darcian water flow in freezing soils
The model of coupled heat transport and Darcian water flow in unsaturated soils and in conditions of freezing and thawing is analyzed. In this contribution, we present results concerning the existence of the numerical solution. Numerical scheme is based on semi-implicit discretization in time. This work illustrates its performance for a problem of freezing processes in vertical soil columns.
Diffuse-interface treatment of the anisotropic mean-curvature flow
We investigate the motion by mean curvature in relative geometry by means of the modified Allen-Cahn equation, where the anisotropy is incorporated. We obtain the existence result for the solution as well as a result concerning the asymptotical behaviour with respect to the thickness parameter. By means of a numerical scheme, we can approximate the original law, as shown in several computational examples.
Direct approach to mean-curvature flow with topological changes
This contribution deals with the numerical simulation of dislocation dynamics. Dislocations are described by means of the evolution of a family of closed or open smooth curves , . The curves are driven by the normal velocity which is the function of curvature and the position. The evolution law reads as: . The motion law is treated using direct approach numerically solved by two schemes, i. e., backward Euler semi-implicit and semi-discrete method of lines. Numerical stability is improved...
Interface dynamics for an anisotropic Allen-Cahn equation
Special issue: Editorial [Czech and Slovak Twin Seminar in Applied Mathematics 2006]
Forced anisotropic mean curvature flow of graphs in relative geometry
The paper is concerned with the graph formulation of forced anisotropic mean curvature flow in the context of the heteroepitaxial growth of quantum dots. The problem is generalized by including anisotropy by means of Finsler metrics. A semi-discrete numerical scheme based on the method of lines is presented. Computational results with various anisotropy settings are shown and discussed.
Computational studies of non-local anisotropic Allen-Cahn equation
The paper presents the results of numerical solution of the Allen-Cahn equation with a non-local term. This equation originally mentioned by Rubinstein and Sternberg in 1992 is related to the mean-curvature flow with the constraint of constant volume enclosed by the evolving curve. We study this motion approximately by the mentioned PDE, generalize the problem by including anisotropy and discuss the computational results obtained.
Computational studies of conserved mean-curvature flow
The paper presents the results of numerical solution of the evolution law for the constrained mean-curvature flow. This law originates in the theory of phase transitions for crystalline materials and describes the evolution of closed embedded curves with constant enclosed area. It is reformulated by means of the direct method into the system of degenerate parabolic partial differential equations for the curve parametrization. This system is solved numerically and several computational studies are...
Czech-Japanese Seminar in Applied Mathematics 2008
The Special Issue of Kybernetika is devoted to the publication of selected peer-reviewed articles submitted by the participants of the Czech-Japanese Seminar in Applied Mathematics 2008 which took place on September 1-7, 2008 in Takachi-ho and Miyazaki, Japan. The Czech-Japanese Seminar in Applied Mathematics 2008 was organized by the Department of Applied Physics, Faculty of Engineering, University of Miyazaki. It was the fourth meeting in the series of the Czech-Japanese Seminars in Applied Mathematics....
Segmentation of MRI data by means of nonlinear diffusion
The article focuses on the application of the segmentation algorithm based on the numerical solution of the Allen-Cahn non-linear diffusion partial differential equation. This equation is related to the motion of curves by mean curvature. It exhibits several suitable mathematical properties including stable solution profile. This allows the user to follow accurately the position of the segmentation curve by bringing it quickly to the vicinity of the segmented object and by approaching the details...
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