Computational fluid dynamics evaluation of excessive dynamic airway collapse

Taherian, Shahab; Rahai, Hamid; Gomez, Bernardo Z.; Waddington, T. C.; Mazdisnian, Farhad

doi:10.1016/j.clinbiomech.2017.10.018

Cited by 8 publications

(4 citation statements)

References 24 publications

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“…The implicit unsteady shear stress transport k - ω turbulence model was used with low Reynolds number modification to model the flow turbulence in normal respiration, as previously described 29,30 . The CFD results for the first patient, excluding the nasal cavity, were correlated with the corresponding experimental data from a light-emitting diode–particle image velocimetry system 31 .…”

Section: Methodsmentioning

confidence: 99%

Evaluation of human obstructive sleep apnea using computational fluid dynamics

et al. 2019

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Obstructive sleep apnea (OSA) severity might be correlated to the flow characteristics of the upper airways. We aimed to investigate the severity of OSA based on 3D models constructed from CT scans coupled with computational fluid dynamics (CFD) simulations. The CT scans of seven adult patients diagnosed with OSA were used to reconstruct the 3D models of the upper airways and CFD modeling and analyses were performed. Results from the fluid simulations were compared with the apnea-hypopnea index. Here we show a correlation between a CFD-based parameter, the adjusted pressure coefficient (Cp*), and the respective apnea-hypopnea index (Pearson’s r = 0.91, p = 0.004), which suggests that the anatomical-based model coupled with CFD could provide functional and localized information for different regions of the upper airways.

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Section: Methodsmentioning

confidence: 99%

Evaluation of human obstructive sleep apnea using computational fluid dynamics

et al. 2019

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“…These investigations were conducted using unsteady Reynolds-averaged Navier–Stokes (RANS) models with a low Reynolds number K-ω turbulence model. 17 Air compressibility can be neglected in these analyses given that air velocity is less than Mach 0.2 in the airways, and upper airway airflow was considered to be adiabatic. Second-order discretization schemes were used for pressure and momentum equations.…”

Section: Methodsmentioning

confidence: 99%

Analysis of the aerodynamic characteristics of the upper airway in obstructive sleep apnea patients

Wen¹,

Wu²,

Li³

et al. 2024

Journal of Dental Sciences

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“…The obstruction in the airway ducts considerably affects the flow dynamics and the mechanics of drug delivery [ 7 , 11 , 40 , 41 ]. Tracheal stenosis is characterized by the narrowing of the tracheal lumen.…”

Section: Introductionmentioning

confidence: 99%

“…Another numerical study, by Taherian, Rahai, Gomez, et al [ 41 ], demonstrated that treatment by stent for excessive dynamic airway collapse improved the breathing conditions, although this was not detected in a spirometry test. Additionally, a study by Taherian, Rahai, Bonifacio, et al [ 40 ], which included experimentally-validated numerical simulations, showed a pressure drop and an increased particle deposition downstream of the stenosis.…”

Section: Introductionmentioning

confidence: 99%

Effect of cartilaginous rings in tracheal flow with stenosis

et al. 2023

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Background In respiratory fluid dynamics research, it is typically assumed that the wall of the trachea is smooth. However, the trachea is structurally supported by a series of cartilaginous rings that create undulations on the wall surface, which introduce perturbations into the flow. Even though many studies use realistic Computer Tomography (CT) scan data to capture the complex geometry of the respiratory system, its limited spatial resolution does not resolve small features, including those introduced by the cartilaginous rings. Results Here we present an experimental comparison of two simplified trachea models with Grade II stenosis (70% blockage), one with smooth walls and second with cartilaginous rings. The use a unique refractive index-matching method provides unprecedented optical access and allowed us to perform non-intrusive velocity field measurements close to the wall (e.g., Particle Image Velocimetry (PIV)). Measurements were performed in a flow regime comparable to a resting breathing state (Reynolds number ReD = 3350). The cartilaginous rings induce velocity fluctuations in the downstream flow, enhancing the near-wall transport of momentum flux and thus reducing flow separation in the downstream flow. The maximum upstream velocity in the recirculation region is reduced by 38%, resulting in a much weaker recirculation zone— a direct consequence of the cartilaginous rings. Conclusions These results highlight the importance of the cartilaginous rings in respiratory flow studies and the mechanism to reduce flow separation in trachea stenosis.

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Computational fluid dynamics evaluation of excessive dynamic airway collapse

Cited by 8 publications

References 24 publications

Evaluation of human obstructive sleep apnea using computational fluid dynamics

Evaluation of human obstructive sleep apnea using computational fluid dynamics

Analysis of the aerodynamic characteristics of the upper airway in obstructive sleep apnea patients

Effect of cartilaginous rings in tracheal flow with stenosis

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