Dynamics of Airflow in a Short Inhalation.

Alister Bates, Denis Doorly, Raul Cetto, Hadrien Calmet, Alberto M Gambaruto, Neil Tolley, Guillaume Houzeaux, Robert Schroter

Research output: Contribution to journalArticle (Academic Journal)peer-review

29 Citations (Scopus)
297 Downloads (Pure)

Abstract

During a rapid inhalation, such as a sniff, the flowin the airways accelerates and
decays quickly. The consequences for flow development and convective transport of an inhaled gas were investigated in a subject geometry extending from the nose to the bronchi. The progress of flow transition and the advance of an inhaled non-absorbed gas were determined using highly resolved simulations of a sniff 0.5 s long, 1 l s21 peak flow, 364 ml inhaled volume. In the nose, the distribution of airflow evolved through three phases: (i) an initial transient of about 50 ms, roughly the filling time for a nasal volume, (ii) quasi-equilibrium over themajority of the inhalation, and (iii) a terminating phase. Flow transition commenced in the supraglottic region within 20 ms, resulting in largeamplitude fluctuations persisting throughout the inhalation; in the nose,
fluctuations that arose nearer peak flow were of much reduced intensity and diminished in the flow decay phase. Measures of gas concentration showed non-uniform build-up and wash-out of the inhaled gas in the nose. At the carina, the form of the temporal concentration profile reflected both shear dispersion and airway filling defects owing to recirculation regions.
Original languageEnglish
Article number20140880
Number of pages15
JournalJournal of the Royal Society Interface
Volume12
Issue number102
Early online date3 Dec 2014
DOIs
Publication statusPublished - 6 Jan 2015

Keywords

  • inspiratory flow
  • respiratory tract
  • airways
  • CFD
  • internal flow
  • transitional flow

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