Search

Start Over Creator Kučera, Václav

2. On numerical solution of compressible flow in time-dependent domains

Creator:
Feistauer, Miloslav, Horáček, Jaromír, Kučera, Václav, and Prokopová, Jaroslava
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
compressible Navier-Stokes equations, arbitrary Lagrangian-Eulerian method, discontinuous Galerkin finite element method, interior and boundary penalty, semi-implicit time discretization, and biomechanics of voice
Language:
English
Description:
We show that dynamical systems in inverse problems are sometimes foliated if the embedding dimension is greater than the dimension of the manifold on which the system resides. Under this condition, we end up reaching different leaves of the foliation if we start from different initial conditions. For some of these cases we have found a method by which we can asymptotically guide the system to a specific leaf even if we start from an initial condition which corresponds to some other leaf. We demonstrate the method by two examples. In the chosen cases of the harmonic oscillator and Duffing's oscillator we find an alternative set of equations which represent a collapsed foliation, such that no matter what initial conditions we choose, the system would asymptotically reach the same desired sub-manifold of the original system. This process can lead to cases for which a system begins in a chaotic region, but is guided to a periodic region and vice versa. It may also happen that we could move from an orbitThe paper deals with numerical simulation of a compressible flow in time-dependent 2D domains with a special interest in medical applications to airflow in the human vocal tract. The mathematical model of this process is described by the compressible Navier-Stokes equations. For the treatment of the time-dependent domain, the arbitrary Lagrangian-Eulerian (ALE) method is used. The discontinuous Galerkin finite element method (DGFEM) is used for the space semidiscretization of the governing equations in the ALE formulation. The time discretization is carried out with the aid of a linearized semi-implicit method with good stability properties. We present some computational results for the flow in a channel, representing a model of glottis and a part of the vocal tract, with a prescribed motion of the channel walls at the position of vocal folds. of one period to an orbit of another period.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public