Large-scale CFD simulations of the transitional and turbulent regime for the large human airways during rapid inhalation

The dynamics of unsteady flow in the human large airways during a rapid inhalation were investigated using highly detailed large-scale computational fluid dynamics on a subject-specific geometry. The simulations were performed to resolve all the spatial and temporal scales of the flow, thanks to the...

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Vydané v:Computers in biology and medicine Ročník 69; s. 166 - 180
Hlavní autori: Calmet, Hadrien, Gambaruto, Alberto M., Bates, Alister J., Vázquez, Mariano, Houzeaux, Guillaume, Doorly, Denis J.
Médium: Journal Article Publikácia
Jazyk:English
Vydavateľské údaje: United States Elsevier Ltd 01.02.2016
Elsevier Limited
Elsevier
Predmet:
Administration, Inhalation
Airways
Behavior
CFD
Computer Simulation
Data processing
Enginyeria electrònica
Fluxos (Sistemes dinàmics diferenciables)
Humans
Impacte ambiental
Inhalation - physiology
Inspiratory flow
Internal Medicine
Large scale systems
Male
Middle Aged
Models, Biological
Nasal Cavity - diagnostic imaging
Nasal Cavity - physiology
Other
Pulmonary Ventilation - physiology
Respiratory airflow
Reynolds number
Simulació, Mètodes de
Tomography
Tomography, X-Ray Computed
Trachea - diagnostic imaging
Trachea - physiology
Turbulence
Turbulent flow
Àrees temàtiques de la UPC
CFD
Airways
Respiratory airflow
Turbulence
Inspiratory flow
ISSN:0010-4825, 1879-0534, 1879-0534
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Shrnutí:The dynamics of unsteady flow in the human large airways during a rapid inhalation were investigated using highly detailed large-scale computational fluid dynamics on a subject-specific geometry. The simulations were performed to resolve all the spatial and temporal scales of the flow, thanks to the use of massive computational resources. A highly parallel finite element code was used, running on two supercomputers, solving the transient incompressible Navier–Stokes equations on unstructured meshes. Given that the finest mesh contained 350 million elements, the study sets a precedent for large-scale simulations of the respiratory system, proposing an analysis strategy for mean flow, fluctuations and wall shear stresses on a rapid and short inhalation (a so-called sniff). The geometry used encompasses the exterior face and the airways from the nasal cavity, through the trachea and up to the third lung bifurcation; it was derived from a contrast-enhanced computed tomography (CT) scan of a 48-year-old male. The transient inflow produces complex flows over a wide range of Reynolds numbers (Re). Thanks to the high fidelity simulations, many features involving the flow transition were observed, with the level of turbulence clearly higher in the throat than in the nose. Spectral analysis revealed turbulent characteristics persisting downstream of the glottis, and were captured even with a medium mesh resolution. However a fine mesh resolution was found necessary in the nasal cavity to observe transitional features. This work indicates the potential of large-scale simulations to further understanding of airway physiological mechanics, which is essential to guide clinical diagnosis; better understanding of the flow also has implications for the design of interventions such as aerosol drug delivery. •Unsteady flow in the human large airways during a rapid inhalation is proposed.•The finest mesh contained 350 million elements.•Thanks to the high fidelity simulations, turbulence and transitional regime are observed.
Bibliografia:ObjectType-Article-1
SourceType-Scholarly Journals-1
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ISSN:0010-4825
1879-0534
1879-0534
DOI:10.1016/j.compbiomed.2015.12.003