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Simulace pohybu velkých vírů při volném proudu
Louda, Petr ; Kozel, K. ; Příhoda, Jaromír
The work deals with large eddy simulation (LES) of incompressible plane free jet issued from a slot nozzle. The mathematical model is based on filtered Navier-Stokes equations. The sub-grid turbulence is modelled by Smagorinsky eddy viscosity model. The numerical solution is carried out by a finite-difference method. The time discretization uses second order accurate 3-stage Runge Kutta scheme. The Poisson equation is used for the estimation of pressure. Various boundary conditions are tested for 2D free jet flow with the Reynolds number Re= 30000. The initial velocity field is randomly perturbed by divergence-free velocity field with maximum value of 0.03Uo.
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Numerical simulation of jet flow using LES
Louda, Petr ; Kozel, K. ; Příhoda, Jaromír
The work deals with the numerical method for the large eddy simulation (LES) of incompressible flow. Governing system of filtered Navier-Stokes equations is completed by the Smagorinsky turbulence model and the Poisson equation is used for pressure instead of the continuity equation. The numerical method is based on an explicit scheme with fourth order accurate central approximation for convection and resolved diffusion. Preliminary results for the plane turbulent free jet are shown. Problem of the prescription of boundary conditions is discussed in detail.
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Numerické řešení sdílení tepla v proudu dopadajícím na stěnu
Kozel, K. ; Louda, Petr ; Příhoda, Jaromír
The paper deals with the numerical solution of 3D impinging turbulent jet cooling a weakly heated wall. The solution was carried out using the SST model and/or an explicit algebraic Reynolds stress model and completed by a generalized gradient-diffusion hypothesis for modelling of turbulent heat flux. While the EARSM model gives good results for the velocity field, all used models overestimate heat transfer in the impingement region.
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Numerické modelování složitých turbulentních proudění
Kozel, K. ; Louda, Petr ; Příhoda, Jaromír
The work deals with the numerical solution of turbulent impinging jet and round jet in a cross flow. The mathematical model is based on averaged Navier-Stokes equations closed by a turbulence model. Turbulence models used are a low-Reynolds-number eddy-viscosity model and/or an explicit algebraic Reynolds stress model. Numerical results are compared with experimental data. In case of impinging jet flow, the heat transfer is also solved.
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Numerické řešení proudění zakřiveným difuzorem
Louda, Petr ; Kozel, K. ; Příhoda, Jaromír
Numerical solution of turbulent flow through a curved diffuser is based on the artificial compressibility method. A cell centered finite volume method is used for spatial discretization. The time discretization uses the backward Euler implicit scheme with turbulence model equations solved decoupled from RANS equations. Results obtained by two different turbulence models - two-equation SST model and EARSM model - are compared and discussed.
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Technical resources for educational support of students with handicap
Louda, Petr ; Šedivá, Zuzana (advisor) ; Žid, Norbert (referee)
This paper deals with evaluation of quality of technical resources to support education of students with handicap at computers. This work aims to map and asses' quality and market appeal of common technical resources for home usage with opinion on less common technical resources for average user and at same time with respect for students with handicap. This publication is divided into four logical parts. First part is devoted to theoretical approach into field of handicaps. From nature of illnesses and handicaps result essential facts, that affects using computers by users with handicap. At the end of this section are noted appropriate ways of using computers. Second part attends to financial seriousness when buying technical resources in this field of purpose. Third section briefly describe method of evaluating products based on first part and define criterion which reflects facts of relevant handicap and at same time also demands of common human user. Fourth part concludes mapping and delivers assessment of chosen products. Publication is completed by trends and facts that affect present market with technical resources.
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