Investigation on the respiratory airflow in human airway by PIV

Kim, S. K.; Chung, Seung‐Kyu

doi:10.1007/bf03181864

Cited by 28 publications

(12 citation statements)

References 23 publications

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“…However, the use of largeeddy simulation (LES) or steady Reynolds-averaged NavierStokes (RANS) turbulence models can reduce the computational cost to simulate the flow within the airway and give accurate predictions of important flow features (Mihaescu et al, 2008;Cui and Gutheil, 2011). The validity of these models has been confirmed against in-vitro measurements in reconstructed airways (Mylavarapu et al, 2009;Kim and Chung, 2009).…”

Section: Introductionmentioning

confidence: 99%

Effect of the velopharynx on intraluminal pressures in reconstructed pharynges derived from individuals with and without sleep apnea

Cisonni

Lucey

Walsh

et al. 2013

Journal of Biomechanics

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The most collapsible part of the upper airway in the majority of individuals is the velopharynx which is the segment positioned behind the soft palate. As such it is an important morphological region for consideration in elucidating the pathogenesis of obstructive sleep apnea (OSA). This study compared steady flow properties during inspiration in the pharynges of 9 male subjects with OSA and 9 body-mass index (BMI)-and age-matched control male subjects without OSA. The k-ω SST turbulence model was used to simulate the flow field in subject-specific pharyngeal geometric models reconstructed from anatomical optical coherence tomography (aOCT) data. While analysis of the geometry of reconstructed pharynges revealed narrowing at velopharyngeal level in subjects with OSA, it was not possible to clearly distinguish them from subjects without OSA on the basis of pharyngeal size and shape alone. By contrast, flow simulations demonstrated that pressure fields within the narrowed airway segments were sensitive to small differences in geometry and could lead to significantly different intraluminal pressure characteristics between subjects. The ratio between velopharyngeal and total pharyngeal pressure drops emerged as a relevant flow-based criterion by which subjects with OSA could be differentiated from those without.

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Section: Introductionmentioning

confidence: 99%

Effect of the velopharynx on intraluminal pressures in reconstructed pharynges derived from individuals with and without sleep apnea

Cisonni

Lucey

Walsh

et al. 2013

Journal of Biomechanics

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“…A myriad of experimental investigations provided valuable descriptions of airflow patterns in the upper airway , but focused mainly on healthy nasal cavity alone or were carried out using idealized airway model. The detailed quantitative information about airflow in realistic anatomical upper airway models concerning abnormal nasal or/and pharyngeal airways is limited.…”

Section: Introductionmentioning

confidence: 99%

Fluid–structure interaction modeling of upper airways before and after nasal surgery for obstructive sleep apnea

Wang

Liu

et al. 2012

Numer Methods Biomed Eng

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Nasal obstruction frequently has been associated with obstructive sleep apnea (OSA). Although correction of an obstructed nasal airway is considered an important component in OSA treatment, the effect of nasal surgery on OSA remains controversial. Variation in airway anatomy between before and after nasal surgery may cause significant differences in airflow patterns within the upper airway. In this paper, anatomically accurate models of the interaction between upper airway and soft palate were developed from prenasal and post-nasal surgery multidetector computed tomography data of a patient with OSA and nasal obstruction. Computational modeling for inspiration and expiration was performed by using fluid-structure interaction method. The airflow characteristics such as velocity, turbulence intensity and pressure drop, and displacement distribution of soft palate are selected for comparison. Airway resistances significantly decrease after the nasal surgery, especially in the velopharynx region because of an enlarged pharyngeal cavity and a reduced upstream resistance. Meanwhile, the decreased aerodynamic force would result in a smaller displacement of soft palates, which would lead to slight impact of the soft palate motion on the airflow characteristics. The present results suggest that airflow distribution in the whole upper airway and soft palate motions have improved following nasal surgery.

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“…We designed a periodic pumping system to generate periodic flow simulating the physiological data of human respiration. [5] In a 2D CT image, nasal airway can be viewed as a collection of separate regions of nasal cavity and paranasal sinus. However, the regions are connected by nasal breathing paths if we construct a 3D model of nasal airway.…”

Section: Methodsmentioning

confidence: 99%

Experimental and Numerical Study on the Nasal Airflows in Post-surgery Models: Simulation of Nasal Surgery

Chung

Kim

et al. 2010

IFMBE Proceedings

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Abstract-Airflows in one normal and six modified models (Post-surgery models) were investigated both experimentally by PIV and numerically by the CFX code. Compared to the normal case, it was found that the fluid and thermodynamic properties (i.e. velocity, surface pressure, surface shear stress, and temperature and humidity distributions) for the postsurgery models changed locally in the nasal cavity. Subsequently, these changes are likely to modify the physiological functions of the nose. Knowledge on stream-wise and time changes of flow-rate, surface pressure and shear stress distributions in the post-surgery models can contribute to the improvement of nasal surgery. The Web-based communication system between multi-researchers and medical doctors is established for making the post-surgery models and to discuss surgery plans. We also introduced a semi-automatic segmentation technique to reconstruct accurate three dimensional computer models from CT data rapidly and conveniently.

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Investigation on the respiratory airflow in human airway by PIV

Cited by 28 publications

References 23 publications

Effect of the velopharynx on intraluminal pressures in reconstructed pharynges derived from individuals with and without sleep apnea

Effect of the velopharynx on intraluminal pressures in reconstructed pharynges derived from individuals with and without sleep apnea

Fluid–structure interaction modeling of upper airways before and after nasal surgery for obstructive sleep apnea

Experimental and Numerical Study on the Nasal Airflows in Post-surgery Models: Simulation of Nasal Surgery

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