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Numerical simulation of the high–frequency oscillatory ventilation in generic models of the human airways

Feldmann, Daniel and Wagner, Claus (2011) Numerical simulation of the high–frequency oscillatory ventilation in generic models of the human airways. 7th International Symposium on Turbulence and Shear Flwo Phenomena (TSFP-7), 28. - 31. July 2011, Ottawa, Canada.

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Official URL: http://www.tsfp7.org/papers.php

Abstract

To improve the understanding of the gas transport mechanisms under conditions of high-frequency oscillatory ventilation (HFOV) we perform numerical simulations of the unsteady flow in simplified models of the human airways using time varying Dirichlet boundary conditions (BC) for the pressure. The flow fields in a generic trachea show excellent agreement with the analytical solution with an average absolute deviation of less than 10^2 for non-dimensional frequencies up to Wo=14. Nonetheless, the computational effort increases for high Wo simulations due to a long relaxation phase and strong velocity gradients near the wall despite of relatively low Reynolds numbers. We also simulated the flow within an endo-tracheal tube comprising turbulent as well as laminar flow behaviour throughout the oscillation cycle. Finally, we used the Dirichlet pressure BCs on multiple open outlets at symmetric bifurcation and three-generation airway models, while guaranteeing mass conservation. Employing identical and slightly different pressure values at the distal bifurcation ends, flow fields are reproduced, similar to that occurring under conditions of uneven physiological behaviour of different lung regions (e.g. pendelluft).

Document Type:Conference or Workshop Item (Speech, Paper)
Title:Numerical simulation of the high–frequency oscillatory ventilation in generic models of the human airways
Authors:
AuthorsInstitution or Email of Authors
Feldmann, Danieldaniel.feldmann@dlr.de
Wagner, Clausclaus.wagner@dlr.de
Date:2011
Refereed publication:No
In ISI Web of Science:No
Page Range:pp. 1-6
Series Name:Conference Proceedings online
Status:Published
Keywords:Bio-Fluid Dynamics, Protective Artificial Respiration (PAR), High Frequency Oscillation Ventilation (HFOV), Numerical Simulation
Event Title:7th International Symposium on Turbulence and Shear Flwo Phenomena (TSFP-7)
Event Location:Ottawa, Canada
Event Type:international Conference
Event Dates:28. - 31. July 2011
Organizer:J. K. Eaton, R. Friedrich, A. V. Johansson, N. Kasagi, H. J. Sung and S. Tavoularis
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics, L - Simulation & Validation
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Fluid Systems
Deposited By: Daniel Feldmann
Deposited On:14 Sep 2011 16:25
Last Modified:12 Dec 2013 21:05

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