Abstract

The objective of this study is to explore the complexity of airflow through the human respiratory tract by carrying out computational fluid dynamics simulation. In order to capture the detailed physics of the flow in this complex system, large eddy simulation (LES) is performed. The crucial step in this analysis is to investigate the impact of breathing transience on the flow field. In this connection, simulations are carried out for transient breathing in addition to peak inspiration and expiration. To enable a fair comparison, the flowrates for constant inspiration/expiration are selected to be identical to the peak flowrates during the transient breathing. Physiologically appropriate regional ventilation for two different flowrates is induced. The velocity field and turbulent flow features are discussed for both flowrates. The airflow through the larynx is observed to be significantly complex with high turbulence level, recirculation, and secondary flow while the level of turbulence decreases through the higher bifurcations.

References

References
1.
Alwan
,
A.
,
Ross
,
A.
,
Resnikoff
,
S.
,
Mendis
,
S.
,
Cruz
,
A. A.
, and
Minelli
,
E.
,
2008
, “
Action Plan of the Global Alliance Against Chronic Respiratory Diseases
,” World Health Organization, Geneva, Switzerland.
2.
Young
,
T.
,
Palta
,
M.
,
Dempsey
,
J.
,
Skatrud
,
J.
,
Weber
,
S.
, and
Badr
,
S.
,
1993
, “
The Occurrence of Sleep-Disordered Breathing Among Middle-Aged Adults
,”
New Engl. J. Med.
,
328
(
17
), pp.
1230
1235
.10.1056/NEJM199304293281704
3.
Gonda
,
I.
,
1992
, “
Targeting by Deposition
,”
Pharm. Inhalation Aerosol Technol.
,
54
, pp.
61
82
.
4.
Weibel
,
E. R.
,
1963
, “
Geometry and Dimensions of Airways of Conductive and Transitory Zones
,”
Morphometry of the Human Lung
,
Springer, Berlin, pp.
110
135
.10.1007/978-3-642-87553-3_10
5.
Horsfield
,
K.
,
Dart
,
G.
,
Olson
,
D. E.
,
Filley
,
G. F.
, and
Cumming
,
G.
,
1971
, “
Models of the Human Bronchial Tree
,”
J. Appl. Physiol.
,
31
(
2
), pp.
207
217
.10.1152/jappl.1971.31.2.207
6.
Johnstone
,
A.
,
Uddin
,
M.
,
Pollard
,
A.
,
Heenan
,
A.
, and
Finlay
,
W.
,
2004
, “
The Flow Inside an Idealised Form of the Human Extra-Thoracic Airway
,”
Exp. Fluids
,
37
(
5
), pp.
673
689
.10.1007/s00348-004-0857-4
7.
Lin
,
C.-L.
,
Tawhai
,
M. H.
,
McLennan
,
G.
, and
Hoffman
,
E. A.
,
2007
, “
Characteristics of the Turbulent Laryngeal Jet and Its Effect on Airflow in the Human Intra-Thoracic Airways
,”
Respir. Physiol. Neurobiol.
,
157
(
2–3
), pp.
295
309
.10.1016/j.resp.2007.02.006
8.
Ball
,
C.
,
Uddin
,
M.
, and
Pollard
,
A.
,
2008
, “
High Resolution Turbulence Modelling of Airflow in an Idealised Human Extra-Thoracic Airway
,”
Comput. Fluids
,
37
(
8
), pp.
943
964
.10.1016/j.compfluid.2007.07.021
9.
Ball
,
C.
,
Uddin
,
M.
, and
Pollard
,
A.
,
2008
, “
Mean Flow Structures Inside the Human Upper Airway
,”
Flow, Turbul. Combust.
,
81
(
1–2
), pp.
155
188
.10.1007/s10494-007-9113-3
10.
Kleinstreuer
,
C.
, and
Zhang
,
Z.
,
2010
, “
Airflow and Particle Transport in the Human Respiratory System
,”
Annu. Rev. Fluid Mech.
,
42
(
1
), pp.
301
334
.10.1146/annurev-fluid-121108-145453
11.
Yu
,
G.
,
Zhang
,
Z.
, and
Lessmann
,
R.
,
1998
, “
Fluid Flow and Particle Diffusion in the Human Upper Respiratory System
,”
Aerosol Sci. Technol.
,
28
(
2
), pp.
146
158
.10.1080/02786829808965517
12.
Stapleton
,
K.-W.
,
Guentsch
,
E.
,
Hoskinson
,
M.
, and
Finlay
,
W.
,
2000
, “
On the Suitability of k–ε Turbulence Modeling for Aerosol Deposition in the Mouth and Throat: A Comparison With Experiment
,”
J. Aerosol Sci.
,
31
(
6
), pp.
739
749
.10.1016/S0021-8502(99)00547-9
13.
Heenan
,
A.
,
Matida
,
E.
,
Pollard
,
A.
, and
Finlay
,
W.
,
2003
, “
Experimental Measurements and Computational Modeling of the Flow Field in an Idealized Human Oropharynx
,”
Exp. Fluids
,
35
(
1
), pp.
70
84
.10.1007/s00348-003-0636-7
14.
Hahn
,
I.
,
Scherer
,
P. W.
, and
Mozell
,
M. M.
,
1993
, “
Velocity Profiles Measured for Airflow Through a Large-Scale Model of the Human Nasal Cavity
,”
J. Appl. Physiol.
,
75
(
5
), pp.
2273
2287
.10.1152/jappl.1993.75.5.2273
15.
Keyhani
,
K.
,
Scherer
,
P.
, and
Mozell
,
M.
,
1995
, “
Numerical Simulation of Airflow in the Human Nasal Cavity
,”
ASME J. Biomech. Eng.
,
117
(
4
), pp.
429
441
.10.1115/1.2794204
16.
Sarangapani
,
R.
,
2000
, “
Modeling Particle Deposition in Extrathoracic Airways
,”
Aerosol Sci. Technol.
,
32
(
1
), pp.
72
89
.10.1080/027868200303948
17.
Xu
,
C.
,
Sin
,
S.
,
McDonough
,
J. M.
,
Udupa
,
J. K.
,
Guez
,
A.
,
Arens
,
R.
, and
Wootton
,
D. M.
,
2006
, “
Computational Fluid Dynamics Modeling of the Upper Airway of Children With Obstructive Sleep Apnea Syndrome in Steady Flow
,”
J. Biomech.
,
39
(
11
), pp.
2043
2054
.10.1016/j.jbiomech.2005.06.021
18.
De Backer
,
J.
,
Vos
,
W.
,
Gorlé
,
C.
,
Germonpré
,
P.
,
Partoens
,
B.
,
Wuyts
,
F.
,
Parizel
,
P. M.
, and
De Backer
,
W.
,
2008
, “
Flow Analyses in the Lower Airways: Patient-Specific Model and Boundary Conditions
,”
Med. Eng. Phys.
,
30
(
7
), pp.
872
879
.10.1016/j.medengphy.2007.11.002
19.
Tanaka
,
G.
,
Ogata
,
T.
,
Oka
,
K.
, and
Tanishita
,
K.
,
1999
, “
Spatial and Temporal Variation of Secondary Flow During Oscillatory Flow in Model Human Central Airways
,”
ASME J. Biomech. Eng.
,
121
(
6
), pp.
565
573
.10.1115/1.2800855
20.
Zhang
,
Z.
, and
Kleinstreuer
,
C.
,
2002
, “
Transient Airflow Structures and Particle Transport in a Sequentially Branching Lung Airway Model
,”
Phys. Fluids
,
14
(
2
), pp.
862
880
.10.1063/1.1433495
21.
Ramuzat
,
A.
, and
Riethmuller
,
M.
,
2002
, “
PIV Investigation of Oscillating Flows Within a 3D Lung Multiple Bifurcations Model
,”
11th International Symposium on Applications of Laser Techniques to Fluid Flows
, Lisbon, Portugal, July 8–11.http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.530.4188
22.
Choi
,
J.
,
Xia
,
G.
,
Tawhai
,
M. H.
,
Hoffman
,
E. A.
, and
Lin
,
C.-L.
,
2010
, “
Numerical Study of High-Frequency Oscillatory Air Flow and Convective Mixing in a CT-Based Human Airway Model
,”
Ann. Biomed. Eng.
,
38
(
12
), pp.
3550
3571
.10.1007/s10439-010-0110-7
23.
Gruetzemacher
,
R. R.
, III
,
2014
,
Numerical Simulation of Human Breathing and Particle Transport Through a CT-Based Pulmonary Airway Geometry
,
The University of Tennessee at Chattanooga
, Chattanooga, TN.https://core.ac.uk/download/pdf/51197177.pdf
24.
Jayaraju
,
S.
,
Brouns
,
M.
,
Lacor
,
C.
,
Belkassem
,
B.
, and
Verbanck
,
S.
,
2008
, “
Large Eddy and Detached Eddy Simulations of Fluid Flow and Particle Deposition in a Human Mouth–Throat
,”
J. Aerosol Sci.
,
39
(
10
), pp.
862
875
.10.1016/j.jaerosci.2008.06.002
25.
Mylavarapu
,
G.
,
Murugappan
,
S.
,
Mihaescu
,
M.
,
Kalra
,
M.
,
Khosla
,
S.
, and
Gutmark
,
E.
,
2009
, “
Validation of Computational Fluid Dynamics Methodology Used for Human Upper Airway Flow Simulations
,”
J. Biomech.
,
42
(
10
), pp.
1553
1559
.10.1016/j.jbiomech.2009.03.035
26.
Lee
,
J.-H.
,
Na
,
Y.
,
Kim
,
S.-K.
, and
Chung
,
S.-K.
,
2010
, “
Unsteady Flow Characteristics Through a Human Nasal Airway
,”
Respir. Physiol. Neurobiol.
,
172
(
3
), pp.
136
146
.10.1016/j.resp.2010.05.010
27.
Mihaescu
,
M.
,
Khosla
,
S. M.
,
Murugappan
,
S.
, and
Gutmark
,
E. J.
,
2010
, “
Unsteady Laryngeal Airflow Simulations of the Intra-Glottal Vortical Structures
,”
J. Acoust. Soc. Am.
,
127
(
1
), pp.
435
444
.10.1121/1.3271276
28.
Zhang
,
Y.
, and
Finlay
,
W. H.
,
2005
, “
Measurement of the Effect of Cartilaginous Rings on Particle Deposition in a Proximal Lung Bifurcation Model
,”
Aerosol Sci. Technol.
,
39
(
5
), pp.
394
399
.10.1080/027868290945785
29.
Azarnoosh
,
J.
,
2016
,
CFD Simulation of the Airflow Through the Human Respiratory Tract
,
The University of Tennessee at Chattanooga
, Chattanooga, TN.https://scholar.utc.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1608&context=theses
30.
Azarnoosh
,
J.
,
Sreenivas
,
K.
, and
Arabshahi
,
A.
,
2016
, “
CFD Investigation of Human Tidal Breathing Through Human Airway Geometry
,”
Procedia Comput. Sci.
,
80
, pp.
965
976
.10.1016/j.procs.2016.05.392
31.
Pointwise
,
2011
, “
T-Rex Hybrid Meshing in Pointwise
,” Pointwise, Fort Worth, TX.
32.
Hyams
,
D. G.
,
Sreenivas
,
K.
,
Pankajakshan
,
R.
,
Nichols
,
D. S.
,
Briley
,
W. R.
, and
Whitfield
,
D. L.
,
2011
, “
Computational Simulation of Model and Full Scale Class 8 Trucks With Drag Reduction Devices
,”
Comput. Fluids
,
41
(
1
), pp.
27
40
.10.1016/j.compfluid.2010.09.015
33.
Ducros
,
F.
,
Nicoud
,
F.
, and
Poinsot
,
T.
,
1998
, “
Wall-Adapting Local Eddy-Viscosity Models for Simulations in Complex Geometries
,”
Numerical Methods for Fluid Dynamics VI
, Oxford University Computing Laboratory, Oxford, UK, pp.
293
299
.https://www.researchgate.net/profile/Nicoud_Franck/publication/248366844_Wall-Adapting_Local_Eddy-Viscosity_Models_for_Simulations_in_Complex_Geometries/links/5501a2ea0cf2d60c0e5f946f.pdf
34.
Xi
,
J.
,
Kim
,
J.
,
Si
,
X. A.
,
Corley
,
R. A.
,
Kabilan
,
S.
, and
Wang
,
S.
,
2015
, “
CFD Modeling and Image Analysis of Exhaled Aerosols Due to a Growing Bronchial Tumor: Towards Non-Invasive Diagnosis and Treatment of Respiratory Obstructive Diseases
,”
Theranostics
,
5
(
5
), pp.
443
455
.10.7150/thno.11107
35.
Womersley
,
J. R.
,
1955
, “
Method for the Calculation of Velocity, Rate of Flow and Viscous Drag in Arteries When the Pressure Gradient is Known
,”
J. Physiol.
,
127
(
3
), pp.
553
563
.10.1113/jphysiol.1955.sp005276
36.
Yin
,
Y.
,
Choi
,
J.
,
Hoffman
,
E. A.
,
Tawhai
,
M. H.
, and
Lin
,
C.-L.
,
2013
, “
A Multiscale MDCT Image-Based Breathing Lung Model With Time-Varying Regional Ventilation
,”
J. Comput. Phys.
,
244
, pp.
168
192
.10.1016/j.jcp.2012.12.007
37.
Barbini
,
P.
,
Brighenti
,
C.
,
Cevenini
,
G.
, and
Gnudi
,
G.
,
2005
, “
A Dynamic Morphometric Model of the Normal Lung for Studying Expiratory Flow Limitation in Mechanical Ventilation
,”
Ann. Biomed. Eng.
,
33
(
4
), pp.
518
530
.10.1007/s10439-005-2511-6
38.
Dubief
,
Y.
, and
Delcayre
,
F.
,
2000
, “
On Coherent-Vortex Identification in Turbulence
,”
J. Turbul.
,
1
(
1
), pp.
011
011
.
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