Numerical simulation of two consecutive nasal respiratory cycles: toward
a beer understanding of nasal physiology
Ludovic de Gabory, MD, PhD
, Nicolas Reville, MD
, Yannick Baux, PhD
, Nicolas Boisson, PhD
Laurence Bordenave, MD, PhD
Background: Computational ﬂuid dynamic (CFD) simula-
tions have greatly improved the understanding of nasal
physiology. We postulate that simulating the entire and re-
peated respiratory nasal cycles, within the whole sinonasal
cavities, is mandatory to gather more accurate observa-
tions and beer understand airﬂow paerns.
Methods: A 3-dimensional (3D) sinonasal model was
constructed from a healthy adult computed tomography
(CT) scan which discretized in 6.6 million cells (mean
volume, 0.008 mm
). CFD simulations were performed
FluentTMv16.0.0 soware with transient and
turbulent airﬂow (k-ω model). Two respiratory cycles
(8 seconds) were simulated to assess pressure, velocity,
wall shear stress, and particle residence time.
Results: The pressure gradients within the sinus cavities
varied according to their place of connection to the main
passage. Alternations in pressure gradients induced a slight
pumping phenomenon close to the ostia but no movement
of air was observed within the sinus cavities. Strong move-
ments were observed within the inferior meatus during ex-
piration contrary to the inspiration, as in the olfactory cle
at the same time. Particle residence time was longer during
expiration than inspiration due to nasal valve resistance, as
if the expiratory phase was preparing the next inspiratory
phase. Throughout expiration, some particles remained in
contact with the lower turbinates. The posterior part of the
olfactory cle was gradually ﬁlled with particles that did not
leave the nose at the next respiratory cycle. This paern in-
creased as the respiratory cycle was repeated.
Conclusion: CFD is more eﬃcient and reliable when the
entire respiratory cycle is simulated and repeated to avoid
2018 ARS-AAOA, LLC.
Computational ﬂuid dynamics (CFD); 3D model; physiol-
ogy; airﬂow; nasal airway; nasal cavity; velocity; wall shear
de Gabory L, Reville N, Baux Y, Boisson N, Bordenave L.
Numerical simulation of two consecutive nasal respiratory
cycles: toward a beer understanding of nasal physiology.
Int Forum Allergy Rhinol. 2018;8:676–685.
Ear, Nose, and Throat (ENT) Department, University Hospital of
opital Pellegrin, Bordeaux, France;
Clinique et d’Innovation Technologique de Bordeaux (CIC-IT 14-01),
University Hospital of Bordeaux, France;
University of Bordeaux,
OPTIFLUIDES, Computational Fluid Dynamics Unit,
Institut National de la Sant
edicale (INSERM), Bioing
enierie tissulaire U1026, Bordeaux, France
Correspondence to: Ludovic de Gabory, MD, PhD, Department of
Rhinology and Plastic Surgery, Centre F-X Michelet, C.H.U. de Bordeaux,
eon, 33075 Bordeaux, France; e-mail:
Additional Supporting Information may be found in the online version of this
Funding sources for the study: Laboratoire de la Mer funded the research
carried out by OPTIFLUIDES.
Potential conﬂict of interest: None provided.
Received: 24 October 2017; Revised: 27 November 2017; Accepted:
14 December 2017
View this article online at wileyonlinelibrary.com.
he nose functions as a dynamic container that con-
stantly interacts with its environment. It is well known
that the passage of the ﬂuid within the nasal cavity deter-
mines the behavior of the respiratory epithelium.
seems to function like a river, water modifying the river bed
and the river bed modifying the movement of water. Un-
like a vessel, the ﬂow is never in the same direction with
the permanent coming and going of air. This is probably
why epithelial cells are perpendicular to the basal lamina
and not oriented toward the ﬂow like endothelial cells.
Moreover, unlike water or blood, air is not visible and the
features of airﬂow require mental representation for the
clinician, in such a way that a computed tomography (CT)
scan shows up anatomy as white and gray while air appears
Computational ﬂuid dynamics (CFD) provide a de-
scription of the movements of ﬂuids, their properties,
physical characteristics, interactions, and all the forces
International Forum of Allergy & Rhinology, Vol. 8, No. 6, June 2018 676