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Steady and unsteady 2D numerical solution of generalized Newtonian fluids flow

Keslerová, RadkaKozel, Karel — 2012

Applications of Mathematics 2012

This article presents the numerical solution of laminar incompressible viscous flow in a branching channel for generalized Newtonian fluids. The governing system of equations is based on the system of balance laws for mass and momentum. The generalized Newtonian fluids differ through choice of a viscosity function. A power-law model with different values of power-law index is used. Numerical solution of the described models is based on cell-centered finite volume method using explicit Runge–Kutta...

Numerical solution of steady and unsteady bypass flow

Prokop, VladimírKozel, Karel — 2004

Programs and Algorithms of Numerical Mathematics

This paper deals with a problem of numerical solution of laminar viscous incompressible stationary and nonstationary flows through a vessel with bypass. One could describe these problems by using model of the Navier-Stokes equations and find a steady solution of an unsteady system by using a multistage Runge-Kutta method together with a time dependent artificial compressibility method. Nonstationary solution is achieved from initial stationary solution by prescribing of nonstationary outlet conditions....

Numerical solution of 2D and 3D incompressible laminar flows through a branching channel

Keslerová, RadkaKozel, Karel — 2004

Programs and Algorithms of Numerical Mathematics

In this paper, we are concerned with the numerical solution of 2D/3D flows through a branching channel where viscous incompressible laminar fluid flow is considered. The mathematical model in this case can be described by the system of the incompressible Navier-Stokes equations and the continuity equation. In order to obtain the steady state solution the artificial compressibility method is applied. The finite volume method is used for spatial discretization. The arising system of ordinary differential...

Numerical simulation of generalized Newtonian and Oldroyd-B fluids flow

Keslerová, RadkaKozel, Karel — 2013

Programs and Algorithms of Numerical Mathematics

This work deals with the numerical solution of generalized Newtonian and Oldroyd-B fluids flow. The governing system of equations is based on the system of balance laws for mass and momentum for incompressible laminar viscous and viscoelastic fluids. Two different definition of the stress tensor are considered. For viscous case Newtonian model is used. For the viscoelastic case Oldroyd-B model is tested. Both presented models can be generalized. In this case the viscosity is defined as a shear rate...

Numerical modelling of viscous and viscoelastic fluids flow through the branching channel

Keslerová, RadkaKozel, Karel — 2015

Programs and Algorithms of Numerical Mathematics

The aim of this paper is to describe the numerical results of numerical modelling of steady flows of laminar incompressible viscous and viscoelastic fluids. The mathematical models are Newtonian and Oldroyd-B models. Both models can be generalized by cross model in shear thinning meaning. Numerical tests are performed on three dimensional geometry, a branched channel with one entrance and two output parts. Numerical solution of the described models is based on cell-centered finite volume method...

On using artificial compressibility method for solving turbulent flows

Louda, PetrKozel, KarelPříhoda, Jaromír — 2012

Applications of Mathematics 2012

In this work, artificial compressibility method is used to solve steady and unsteady flows of viscous incompressible fluid. The method is based on implicit higher order upwind discretization of Navier-Stokes equations. The extension for unsteady simulation is considered by increasing artificial compressibility parameter or by using dual time stepping. The methods are tested on laminar flow around circular cylinder and used to simulate turbulent unsteady flows by URANS approach. The simulated cases...

Numerical comparison of unsteady compressible viscous flow in convergent channel

Pořízková, PetraKozel, KarelHoráček, Jaromír — 2012

Applications of Mathematics 2012

This study deals with a numerical solution of a 2D flows of a compressible viscous fluids in a convergent channel for low inlet airflow velocity. Three governing systems – Full system, Adiabatic system, Iso-energetic system b a s e d o n t h e N a v i e r - S t o k e s e q u a t i o n s f o r l a m i n a r f l o w a r e t e s t e d . T h e n u m e r i c a l s o l u t i o n i s r e a l i z e d b y f i n i t e v o l u m e m e t h o d a n d t h e p r e d i c t o r - c o r r e c t o r M a c C o r m a c k s c h e m e w i t h J a m e s o n a r t i f i c i a l v i s c o s i t y u s i n g a g r i d o f q u a d r i l a t e r a l c e l l s . T h e u n s t e a d y g r i d o f q u a d r i l a t e r a l c e l l s i s c o n s i d e r e d i n t h e f o r m o f c o n s e r v a t i o n l a w s u s i n g A r b i t r a r y L a g r a n g i a n - E u l e r i a n m e t h o d . T h e n u m e r i c a l r e s u l t s , a c q u i r e d f r o m a d e v e l o p e d p r o g r a m , a r e p r e s e n t e d f o r i n l e t v e l o c i t y u=4.12 ms-1 a n d R e y n o l d s n u m b e r R e = 4 103 .

Numerical solution of inviscid incompressible flow in a channel with dynamical effects

Honzátko, RadekHoráček, JaromírKozel, Karel — 2004

Programs and Algorithms of Numerical Mathematics

Numerical solution of unsteady 2D inviscid incompressible flows described by Euler equations over the vibrating profile NACA 0012 in a channel is studied. The finite volume method (FVM) and a higher order cell-centered scheme with an artificial dissipation at a qudrilateral C-mesh is used. The method of artificial compressibility and the time dependent method are used for steady state solutions. Numerical results are compared with experimental data.

An unsteady numerical solution of viscous compressible flows in a channel

Punčochářová, PetraKozel, KarelFürst, JiříHoráček, Jaromír — 2006

Programs and Algorithms of Numerical Mathematics

The work deals with numerical solution of unsteady flows in a 2D channel where one part of the channel wall is changing as a given function of time. The flow is described by the system of Navier-Stokes equations for compressible (laminar) flows. The flow has low velocities (low Mach numbers) and is numerically solved by the finite volume method. Moving grid of quadrilateral cells is considered in the form of conservation laws using ALE (Arbitrary Lagrangian-Eulerian) method.

Numerical solution of several models of internal transonic flow

Jaroslav FořtKarel Kozel — 2003

Applications of Mathematics

The paper deals with numerical solution of internal flow problems. It mentions a long tradition of mathematical modeling of internal flow, especially transonic flow at our department. Several models of flow based on potential equation, Euler equations, Navier-Stokes and Reynolds averaged Navier-Stokes equations with proper closure are considered. Some mathematical and numerical properties of the model are mentioned and numerical results achieved by in-house developed methods are presented.

High order finite volume schemes for numerical solution of 2D and 3D transonic flows

Jiří FürstKarel KozelPetr Furmánek — 2009

Kybernetika

The aim of this article is a qualitative analysis of two modern finite volume (FVM) schemes. First one is the so called Modified Causon’s scheme, which is based on the classical MacCormack FVM scheme in total variation diminishing (TVD) form, but is simplified in such a way that the demands on computational power are much smaller without loss of accuracy. Second one is implicit WLSQR (Weighted Least Square Reconstruction) scheme combined with various types of numerical fluxes (AUSMPW+ and HLLC)....

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