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Incompressible fiscous flow at viscous velocities in interaction with a vibrating profile NACA 0012
Honzátko, R. ; Horáček, Jaromír ; Kozel, Karel
The work presents numerical solution of the interaction of 2D incompressible viscous flow and a freely vibrating profile NACA 0012 with large amplitudes. The upstream flow velocities are consider in the range 5-40 m/s. The profile has two degrees of freedom. It can rotate around an elastic axis and oscillate in the vertical direction. Its motion is described by two nonlinear ordinary differential equations. Fourth-order Runge-Kutta method is used to solve these equations numerically. The incompressible Navier-Stokes equations represent the mathematical model of the laminar viscous flow. Numerical schemes of the FVM are applied on a structured Quadrilateral C-mesh. The method of artificial compressibility and dual-time stepping method is employed for numerical simulations. Deformations of the computational domain are treated using the ALE method. Numerical simulations of the profile motion are performed for the case solved earlier by the FE method, and the results are in good agreement.
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Numerical simulation of unsteady low-Mach number viscous flow in a channel
Punčochářová, P. ; Kozel, Karel ; Horáček, Jaromír ; Fürst, J.
This study deals with a numerical solution of a 2D unsteady flow of a compressible viscous fluid in a channel for low inlet airflow velocity. The unsteadiness of the flow is caused by a prescribed periodic motion of a part of the channel wall with large amplitudes, nearly closing the channel during oscillations. The channel is a simplified model of the glottal space in the human vocal and the flow can represent a model of airflow coming from the trachea, through the glottal region with periodically vibrating vocal folds to the human vocal tract. The flow is described by a system of Navier-Stokes equations for laminar flows. The numerical solution is implemented using a grid of quadrilateral cells. Due the motion of the grid, the basic equations are considered in the Arbitrary Lagrangian-Eulerian form. Numerical results are presented for Mach number 0,012m, Reynolds number 5000 and vibration frequency 100 Hz.
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Numerické simulace interakce neviskozního a viskozního proudění nestlačitelné tekutiny s vibrujícím profilem
Honzátko, R. ; Horáček, Jaromír ; Kozel, Karel
The work deals with a numerical solution of the interaction of 2D incompressible flows and a freely vibrating profile with large amplitudes. The profile can oscillate around an elastic axis and in the vertical direction. The motion of the profile is described by two nonlinear ordinary differential equations solved numerically using four-order Runge-Kutta method. The Euler or Navier-Stokes equations represent the inviscid or viscous flows. Numerical schemes of the finite volume method are applied on a structured quadrilateral C-mesh. The method of artificial compressibility and dual-time stepping method are employed for numerical solution. Deformations of the computational domain due to the profile motion are treated using the ALE method.
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Numerická simulace stlačitelného proudění s nízkým Machovým číslem skrz oscilující štěrbinu
Punčochářová, Petra ; Fürst, J. ; Kozel, Karel ; Horáček, Jaromír
The work deals with the numerical solution of 2D unsteady compressible viscous flows in a symmetric channel for a low inlet airflow velocity. The unsteadiness of the flow is caused by a prescribed periodic motion of a part of the channel wall with large amplitudes, nearly closing the channel during the oscillations. The flow in the channel can represent a simplified model of airflow coming from the trachea, through the glottal region with periodically vibratin vocal folds to the human vocal tract. The numerical solution is realized by finite volume method and the explicit predictor-corrector MacCormack scheme with Jameson artificial viscosity using a grid of quadrilateral cells. The moved grid of quadrilateral cells is considered in the form of conservation laws using Arbitrary Lagrangian-Eulerian method.
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Numerické řešení stacionárního a nestacionárního proudění kolem profilu v kanálu
Furmánek, P. ; Horáček, Jaromír ; Kozel, Karel
The work deals with steady and unsteady solution of subsonic flow over a profile DCA 18%in a channel. For the computation the predictor-correstor MacCormack scheme with modified TVD Cousonś artificial dissipation is used. Firstly, the steady state solution compared to the experimental results is presented. Than a simple unsteady model based on pressure change at the outlet area of the computational domain and finaly an unsteady model obtained with the use of ALE method (moving mesh) are presented.
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Numerické řešení stacionárního a nestacionárního stlačitelného viskozního proudění v kanále
Punčochářová, P. ; Kozel, Karel ; Horáček, Jaromír ; Fürst, J.
This study deals with numerical solution of 2D unsteady flow of compressible viscous fluid in channel for a low inlet airflow velocity. The unsteadiness of the flow is caused by a prescribed periodic motion of a part of the channel wall with large amplitudes. The channel is harmonically opening and nearly closing. When closing the airlow velocity is becoming much higher in the narrowest part of the airways, where also the viscous forces play important role. Therefore for a correct modelling of a real flow the compressible, viscous and unsteady fluid-flow model decribed by Navire-Stokes equations should be considered. The authors present the simulations of the flow field by the expecially developed program.
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Numerické řešení vybraných problémů vnější a vnitřní aerodynamiky
Furmánek, P. ; Fürst, J. ; Horáček, Jaromír ; Kozel, Karel
The work deals with numerical solution of transonic flows around a DCA 18% profile and over a wing (modified NACA 0012) in the wall. The numerical solution is based on MacCormack finite volumes prdictor-corrector scheme with Jameson's artifficial dissipation. We present several results of subsonic and transonic flow over DCA 18% in the channel compared to the experimental results of Institute of Thermomechanics. Next simulation considers 3D transonic flow over a wing with two different angles of attack.
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