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Numerical Solution of 3D Airflow in Channel Representing a Vocal Tract
Pořízková, P. ; Kozel, Karel ; Horáček, Jaromír
This study deals with the numerical solution of a 3D compressible flow of a viscous fluid in a channel for low inlet airfloe velocity. the channel is a simplified model of the glottal space in the human vocal tract. The system of Navier-Stokes equations has been used as mathematical model of laminar flow of the compressible viscous fluid in a domain. The numerical solution is implemented using the finite volume method (FVM)and the predictor-corrector MacCormack scheme with artifical viscosity using a grid of quadrilateral cells.
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Numerical solution of compressible subsonic flows in 3D channel
Pořízková, P. ; Kozel, K. ; Horáček, Jaromír
The channels shape is a simplified geometry of the glottal space in the human vocal tract. Goal is numerical simulation of flow in the channels which involves attributes of real flow causing acoustic perturbations. The system of Navier-Stokes equations closed with static pressure expression for ideal gas describes the unsteady laminar flow of compressible viscous fluid. The numerical solution is implemented using the finite volume method and the predictor-corrector MacCormack scheme with artificial viscosity using a grid of quadrilateral cells. The unsteady grid of quadrilateral cells is considered in the form of conservation laws using Arbitrary Lagrangian-Eulerian method.
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Unsteady flows in convergent channel with stationary walls
Pořízková, P. ; Kozel, Karel ; Horáček, Jaromír
A current challenging question is a mathematical and physical description of the mechanism for transforming the airflow energy in human vocal tract (convergent channel) into the acoustic energy representing the voice source in humans. Goal of this work is to describe mathematical model of flow in 2D convergent channel which involves attributes of real flow as is “Coanda phenomenon”, vortex convection and diffusion, jet flapping etc. along with lower call on computer time, due to later extension in 3D channel flow.
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Numerical comparison of unsteady compressible viscous flow in convergent channel
Pořízková, P. ; Kozel, Karel ; Horáček, Jaromír
This study deals with a numerical solution of a 2D flows a compressible viscous fluids in a convergent channel for low inlet airflow velocity. Three governing systems – Full system, Adiabatic system, Iso-energetic system based on the Navier-Stokes equations for laminar flow are tested. The numerical solution is realized by finite volume method and the predictor-corrector MacCormack scheme with Jameson artificial viscosity using a gird of quadrilateral cells. This unsteady grid of quadrilateral cells is considered in the form of conservation laws using Arbitrary Lagrangian-Eulerian method. The numerical results, acquired from a developed program. Are presented for inlet velocity ûĄ = 4,12ms-1 and Reynolds number Re = 4 x 103.
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Numerical experiment of compressible flow in convergent channel- pressure spectral analysis
Pořízková, P. ; Kozel, Karel ; Horáček, Jaromír
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 flow is described by the system of Navier-Stokes equations for laminar flows. The numerical solution is implemented using the finite volume method (FVM) and the predictor-corrector MacCormack scheme with Jameson artificial viscosity using a gird of quadrilateral cells. The numerical results of unsteady flows in the channel are presented for inlet velocity uĄ = 4.12m/s, inlet Reynolds number ReĄ = 4481 and wall motion frequency 100Hz.
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Numerical experiment of flow Mach in vocal tract
Pořízková, P. ; Kozel, K. ; Horáček, Jaromír
This study deals with the 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, nearly closing the channel during oscillations. The channel is a simplified model of the glottal space in the human vocal tract. The flow is described by the full system of Navier-Stokes equations or by adiabatic system equations.
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Numerical computation and comparison of low Mach number flow in a channel
Pořízková, P. ; Kozel, K. ; Horáček, Jaromír
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 tract. The authors present unsteady numerical solutions of flow in two similar computational domains. The numerical results are presented for inlet Mach number MĄ = 0.012, Reynolds number Re = 4481 and the wall motion frequency 100 Hz.
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Numerical tests of flow in human vocal tract
Pořízková, P. ; Kozel, K. ; Horáček, Jaromír
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 tract. The authors present several numerical tests of computational domain, of modified numerical scheme and types of mesh for the wall motion frequency 100 Hz.
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