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Cesenek J.,Aerospace Research and Test Establishment
EPJ Web of Conferences | Year: 2014

In this paper we deal with numerical simulation of the compressible viscous flow. The mathematical model of flow is represented by the system of non-stationary compressible Navier-Stokes equations. This system of equations is discretized by the discontinuous Galerkin finite element method in space and in time using piecewise polynomial discontinuous approximations. We present some numerical experiments to demonstrate the applicability of the method using own-developed code. © 2014 EDP Sciences. Source


Straka P.,Aerospace Research and Test Establishment | Prihoda J.,Czech Institute of Thermomechanics
EPJ Web of Conferences | Year: 2016

The contribution deals with the simulation of the laminar/turbulent transition taking into account the effect of wall roughness. The correlation for the transition onset proposed by Straka and Příhoda [1] was modified for the effect of the wall roughness using the correlation according to Boyle and Stripf [2]. This correlation derived for the wall roughness formed by regularly distributed truncated cones was modified for flows over the distributed wall roughness. The algebraic transition model proposed by Straka and Příhoda [1] with the modified relation for the transition onset was verified by means of the incompressible flat-plate boundary-layer and the compressible flow through the turbine blade cascade with rough blades. © 2016 Owned by the authors, published by EDP Sciences. Source


Cesenek J.,Aerospace Research and Test Establishment
EPJ Web of Conferences | Year: 2016

In this article we deal with numerical simulation of the non-stationary compressible turbulent flow. Compressible turbulent flow is described by the Reynolds-Averaged Navier-Stokes (RANS) equations. This RANS system is equipped with two-equation k-omega turbulence model. These two systems of equations are solved separately. Discretization of the RANS system is carried out by the space-time discontinuous Galerkin method which is based on piecewise polynomial discontinuous approximation of the sought solution in space and in time. Discretization of the two-equation k-omega turbulence model is carried out by the implicit finite volume method, which is based on piecewise constant approximation of the sought solution. We present some numerical experiments to demonstrate the applicability of the method using own-developed code. © 2016 Owned by the authors, published by EDP Sciences. Source


Podzimek J.,Aerospace Research and Test Establishment
Engineering Against Failure - Proceedings of the 3rd International Conference of Engineering Against Failure, ICEAF 2013 | Year: 2013

Today's higher requirements for environmental friendly solutions force manufacturers to look for alternatives. One of them was the replacement of a lead sealing in an aerial turboprop engine with a polytetrafluoroethylene (PTFE) alternative. The task was to bond steel and PTFE and to make a durable bond under different temperature conditions. There were certain difficulties due to the mechanical and chemical properties of PTFE, and this lecture describes the evolution from submission through testing towards the solution of this problem, as well as some basic design ideas and principles. Source


Cesenek J.,Charles University | Cesenek J.,Aerospace Research and Test Establishment | Feistauer M.,Charles University | Kosik A.,Charles University
ZAMM Zeitschrift fur Angewandte Mathematik und Mechanik | Year: 2013

The subject of the paper is the numerical simulation of the interaction of two-dimensional compressible viscous flow and a vibrating airfoil. A solid airfoil with two degrees of freedom performs rotation around an elastic axis and oscillations in the vertical direction. The numerical simulation consists of the solution of the Navier-Stokes system by the discontinuous Galerkin method coupled with a system of nonlinear ordinary differential equations describing the airfoil motion. The time-dependent computational domain and a moving grid are taken into account by the arbitrary Lagrangian-Eulerian (ALE) formulation of the Navier-Stokes equations. The developed method is robust with respect to the magnitude of the Mach number and Reynolds number. Its applicability is demonstrated by numerical experiments. The subject of the paper is the numerical simulation of the interaction of two-dimensional compressible viscous flow and a vibrating airfoil. A solid airfoil with two degrees of freedom performs rotation around an elastic axis and oscillations in the vertical direction. The numerical simulation consists of the solution of the Navier-Stokes system by the discontinuous Galerkin method coupled with a system of nonlinear ordinary differential equations describing the airfoil motion. The time-dependent computational domain and a moving grid are taken into account by the arbitrary Lagrangian-Eulerian (ALE) formulation of the Navier-Stokes equations. The developed method is robust with respect to the magnitude of the Mach number and Reynolds number. Its applicability is demonstrated by numerical experiments. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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