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Start Over Subject numerical solution

1. A numerical investigation of a buoyancy driven flow in a semi-porous cavity: comparative effects of ramped and isothermal wall conditions

Creator:
Chandran, Pallath, Sacheti, Nirmal C., and Singh, Ashok K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
rectangular cavity, free convection, brinkman model, coupled flow, ramped boundary condition, and numerical solution
Language:
Slovak
Description:
Steady two-dimensional natural convection taking place in a rectangular cavity, partially filled with an isotropic porous material, has been investigated numerically using an ADI method. It is assumed that one of the vertical walls of the cavity has a ramped temperature distribution. The vorticity-stream function formulation has been used to solve the set of nonlinear partial differential equations governing the flows in the clear region and the adjoining porous region. The effects of Darcy number and Rayleigh number have been discussed in detail.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Finite-volume level set method and its adaptive version in completing subjective contours

Creator:
Krivá, Zuzana
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
image processing, nonlinear partial differential equations, numerical solution, finite volume method, adaptivity, and grid coarsening
Language:
English
Description:
In this paper we deal with a problem of segmentation (including missing boundary completion) and subjective contour creation. For the corresponding models we apply the semi-implicit finite volume numerical schemes leading to methods which are robust, efficient and stable without any restriction to a time step. The finite volume discretization enables to use the spatial adaptivity and thus improve significantly the computational time. The computational results related to image segmentation with partly missing boundaries and subjective contour extraction are presented.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Numerical analysis of a semi-implicit DDFV scheme for the regularized curvature driven level set equation in 2D

Creator:
Handlovičová, Angela and Kotorová, Dana
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
mean curvature flow, level set equation, numerical solution, semi-implicit scheme, discrete duality finite volume method, stavility, and convergence
Language:
English
Description:
Stability and convergence of the linear semi-implicit discrete duality finite volume (DDFV) numerical scheme in 2D for the solution of the regularized curvature driven level set equation is proved. Numerical experiments concerning comparison with exact solution and image filtering problem using proposed scheme are included.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Numerical solution of inviscid and viscous flows using modern schemes and quadrilateral or triangular mesh

Creator:
Fürst, J. and Kozel, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
transonic flow, Euler equations, Navier-Stokes equations, numerical solution, TVD, and ENO
Language:
English
Description:
This contribution deals with the modern finite volume schemes solving the Euler and Navier-Stokes equations for transonic flow problems. We will mention the TVD theory for first order schemes and some numerical examples obtained by 2D central and upwind schemes for 2D transonic flows in the GAMM channel or through the SE 1050 turbine of Škoda Plzeň. The TVD MacCormack method is extended to a 3D method for solving flows through turbine cascades. Numerical examples of unsteady transonic viscous (laminar) flows through the DCA 8% cascade are also presented for Re = 4600. Next, a new finite volume implicit scheme is presented for the case of unstructured meshes (with both triangular and quadrilateral cells) and inviscid compressible flows through the GAMM channel as well as the SE 1050 turbine cascade.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5. Numerical solution of modified Fokker-Planck equation with Poissonian input

Creator:
Náprstek, Jiří and Král, Radomil
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Fokker-Planck equation, Poissonian excitation, numerical solution, and transition effects
Language:
English
Description:
The paper makes a sketch of an SDOF system response analysis subjected to a random excitation having a form of the additive Poisson driven independent random impulses. A special generalised Fokker-Planck equation having a form of an integro-differential equation is presented together with boundary and initial conditions. Later the Galerkin-Petrov process as a method of a numerical solution of the respective evolutionary integro-differential equation for the probability density function (PDF) is presented in general. Various analytic and semi-analytic solution methods have been developed for various systems to obtain results requested. However numerical approaches offer a powerful altemative. In particular the Finite Element Method (FEM) seems to be very effective. Shape and weighting functions for purposes of a numerical solution procedure are carred out and corresponding ordinary differential system for PDF values in nodes is deduced. As a demonstration particular SDOF systems are investigated. Resulting PDFs are analysed and mutually compared. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Some instances of the Fokker-Planck equation numerical analysis for systems with Gaussian noises

Creator:
Náprstek, Jiří and Král, Radomil
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Fokker-Planck equation, numerical solution, and transition effects
Language:
English
Description:
The Fokker-Planck (FP) equation is frequently used when the response of the dynamic system subjected to additive and/or multiplicative ramdom noises is investiagted. It provides the probability density function (PDF) representing the key information for further study of the dynamic system. Various analytic and semi-analytic solution methods have been developed for various systems to obtain results requested. However numerical approaches offer a powerful alternative. In particular the Finite Element Method (FEM) seems to be very effective. A couple of single dynamic linear/non-linear systems under additive and multiplicative random excitations are discussed using FEM as a solution tool of the FP equation. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. The stability analysis of a discretized pantograph equation

Creator:
Jánský, Jiří and Kundrát, Petr
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
pantograph equation, numerical solution, and stability
Language:
English
Description:
The paper deals with a difference equation arising from the scalar pantograph equation via the backward Euler discretization. A case when the solution tends to zero but after reaching a certain index it loses this tendency is discussed. We analyse this problem and estimate the value of such an index. Furthermore, we show that the utilized proof technique enables us to investigate some other numerical formulae, too.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public