An investigation of the relationship between the flow field and regional deposition in realistic extra-thoracic airways

Heenan, A.F.; Finlay, Warren H.; Grgic, B.; Pollard, A.; Burnell, P.K.P.

doi:10.1016/j.jaerosci.2004.03.004

Cited by 61 publications

(32 citation statements)

References 14 publications

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“…(2004)). In S1a, we note the absence of a jet in both experimental and numerical results, and an increase in the velocity further downstream in the larynx (figure 7 herein and figure 6 by Heenan et al (2004)). The only discrepancy between the two sets of results is in the oral cavity in S1a, where the impingement of the inlet flow on the front of the tongue is inappreciable in the PIV measurements due to the wider inlet pipe used in the experiments.…”

Section: Intrasubject Variationmentioning

confidence: 74%

“…For the medium-sized particles, deposition in the mouth, pharynx and larynx is significantly higher in S1b, via impaction due to the pharyngeal jet. The fact that this significant difference in deposition between S1a and S1b isn't also observed for the largest-sized particles is somewhat anomalous, as mentioned by Grgic et al (2004a), who cited the large variation in regional deposition and flow field measurements reported by Heenan et al (2004). Deposition in the trachea is higher in S1a due to the high-velocity separated shear layer that forms at the sharp step in the larynx (see location D1-D2 in figure 6).…”

Section: Intrasubject Variationmentioning

confidence: 84%

“…Finally, the separated shear layer in the trachea of S1a was not reported by Heenan et al (2004) as their PIV measurements focused on the upstream region of the flow.…”

Section: Intrasubject Variationmentioning

confidence: 93%

“…Whereas Jayaraju et al (2008) found considerable improvement in predicting deposition for smaller particles and Cui & Gutheil (2011) showed better predictions particularly in the transitional regime using LES over RANS, Debhi (2011) obtained comparable accuracy between RANS and LES models. In addition, experiments have demonstrated the large effect that geometric complexity has on the flow, and hence deposition (Heenan et al, 2004;Grgic et al, 2004b). Therefore the simplified geometries adopted in earlier work is not sufficient.…”

Section: Introductionmentioning

confidence: 99%

“…A number of in vivo (Walsh et al, 1977;Foord et al, 1978;Chan & Lippmann, 1980;Stahlhofen et al, 1980Stahlhofen et al, , 1981Emmett & Aitken, 1982;Svartengren et al, 1994;Dunbar et al, 2002) and in vitro studies (Cheng et al, 1999(Cheng et al, , 2001Lin et al, 2001;Grgic et al, 2004b;DeHaan & Finlay, 2004;Grgic et al, 2004a;Heenan et al, 2004;Zhang et al, 2007;Zhou et al, 2011;Shinneeb & Pollard, 2012) have been conducted in order to develop an understanding of the flow and particle dynamics in the extrathoracic airways. In vivo experiments are costly and complex to perform, and accurate results are difficult to obtain due to spatial resolution and tissue attenuation limit (Grgic et al, 2004b).…”

Section: Introductionmentioning

confidence: 99%

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Direct numerical simulations of flow in realistic mouth–throat geometries

Nicolaou

Zaki

2013

Journal of Aerosol Science

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Section: Intrasubject Variationmentioning

confidence: 74%

Section: Intrasubject Variationmentioning

confidence: 84%

“…Finally, the separated shear layer in the trachea of S1a was not reported by Heenan et al (2004) as their PIV measurements focused on the upstream region of the flow.…”

Section: Intrasubject Variationmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Direct numerical simulations of flow in realistic mouth–throat geometries

Nicolaou

Zaki

2013

Journal of Aerosol Science

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Airway Gas Flow

Tawhai

Lin

2011

Comprehensive Physiology

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Local characteristics of airflow and its global distribution in the lung are determined by interaction between resistance to flow through the airways and the compliance of the tissue, with tissue compliance dominating flow distribution in the healthy lung. Current understanding is that conceptualizing the airways of the lung as a system of smooth adjoined cylinders through which air traverses laminarly is insufficient for understanding flow and energy dissipation and is particularly poor for predicting physiologically realistic transport of particles by the airflow. With rapid advances in medical imaging, computer technologies, and computational techniques, computational fluid dynamics is now becoming a viable tool for providing detailed information on the mechanics of airflow in the human respiratory tract. Studies using such techniques have shown that the upper airway (specifically its development of a turbulent laryngeal jet in the trachea), airway geometry, branching and rotation angle, and the pattern of joining of successive bifurcations are important in determining airflow structures. It is now possible to compute airflow in physical domains that are anatomically accurate and subject specific, enabling comparisons among intersubjects, that among subjects of different ages, and that among different species.

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The lung physiome: merging imaging‐based measures with predictive computational models

Tawhai

Hoffman

Lin

2009

WIREs Mechanisms of Disease

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Global measurements of the lung provided by standard pulmonary function tests do not give insight into the regional basis of lung function and lung disease. Advances in imaging methodologies, computer technologies, and subject-specific simulations are creating new opportunities for studying structure-function relationships in the lung through multi-disciplinary research. The digital Human Lung Atlas is an imaging-based resource compiled from male and female subjects spanning several decades of age. The Atlas comprises both structural and functional measures, and includes computational models derived to match individual subjects for personalized prediction of function. The computational models in the Atlas form part of the Lung Physiome project, which is an international effort to develop integrative models of lung function at all levels of biological organization. The computational models provide mechanistic interpretation of imaging measures; the Atlas provides structural data upon which to base model geometry, and functional data against which to test hypotheses. The example of simulating air flow on a subject-specific basis is considered. Methods for deriving multi-scale models of the airway geometry for individual subjects in the Atlas are outlined, and methods for modeling turbulent flows in the airway are reviewed.

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An investigation of the relationship between the flow field and regional deposition in realistic extra-thoracic airways

Cited by 61 publications

References 14 publications

Direct numerical simulations of flow in realistic mouth–throat geometries

Direct numerical simulations of flow in realistic mouth–throat geometries

Airway Gas Flow

The lung physiome: merging imaging‐based measures with predictive computational models

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