2026-04-13T12:33:52Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/849512026-01-22T04:43:50Zcom_2072_1033col_2072_452950

Dynamics of Airflow in a Short Inhalation Bates, Alister J. Doorly, Denis J. Cetto, Raul Calmet, Hadrien Gambaruto, Alberto Tolley, Neil Houzeaux, Guillaume Schroter, Robert Àrees temàtiques de la UPC::Enginyeria biomèdica Biomechanics Transitional flow Inspiratory flow Respiratory tract Airways CFD Internal flow Transitional flow Gasos--Flux 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. This research was supported by EPSRC Doctoral Training Award EP/P505550/1. Electronic supplementary material is available at http://dx.doi.org/10.1098/rsif.2014.0880 or via http://rsif.royalsocietypublishing.org. Peer Reviewed Postprint (published version) 2015-01-06 Article http://rsif.royalsocietypublishing.org/content/12/102/20140880.article-info The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. https://creativecommons.org/licenses/by/4.0/ Open Access Attribution 4.0 International License The Royal Society