Jaromír Horáček

The ALE Discontinuous Galerkin Method for the Simulatio of Air Flow Through Pulsating Human Vocal Folds

The aim of this work is the simulation of viscous compressible flows in human vocal folds during phonation. The computational domain is a bounded subset of IR2, whose geometry mimics the shape of the human larynx. During phonation, parts of the solid impermeable walls are moving in a prescribed manner, thus simulating the opening and closing of the vocal chords. As the governing equations we take the compressible Navier‐Stokes equations in ALE form. Space semidiscretization is carried out by the discontinuous Galerkin method combined with a linearized semi‐implicit approach. Numerical experiments are performed with the resulting scheme.

On mathematical modeling of fluid-structure interactions with nonlinear effects

In this paper the numerical simulation of aeroelastic interactions of flexibly supported two-degrees of freedom (2-DOF) airfoil in two-dimensional (2D) incompressible viscous turbulent flow subjected to a gust (sudden change of flow conditions) is considered. The flow is modeled by Reynolds averaged Navier-Stokes equations (RANS), and by k - ω turbulence model. The considered flow problem is discretized in space using the fully stabilized finite element (FE) method implemented in the developed in-house program, which allows to solve interaction problems. In order to treat the time dependent inlet boundary condition the standard stabilization procedure was modified. Further, the under relaxation procedure was introduced in order to overcome the artificial instability of the coupling algorithm. The aeroelastic response to a sudden gust is numerically analyzed with the aid of the developed FE code.

Compressible Flows of Viscous Fluid in 3D Channel

This study deals with the numerical solution of a 3D compressible flow of a viscous fluid in a channel for low inlet airflow 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 artificial viscosity using a grid of hexahedral cells. The numerical simulations of flow fields in the channel, acquired from a developed program, are presented for inlet velocity \(\hat{u}_{\infty } = 4.12\,\mathrm{ms}^{-1}\) and Reynolds number \(\mathrm{Re}_{\infty } = 4,481\).

Mathematical Modeling of Flow in Human Vocal Tract

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 is caused by a prescribed periodic motion of the channel wall. Unsteady flow fields for inlet Mach number M ∞ = 0. 012 and frequency 100 Hz are presented.