Computational fluid dynamics investigation of particle intake for nasal breathing by a moving body

AbstractAnterior rhinomanometry is the current gold standard for the objective assessment of nasal breathing by determining the nasal resistance. However, computational fluid dynamics would allow spatially and temporally well- resolved investigation of additional flow parameters. In this study, measured values of nasal resistance are compared with measured values. An unclear discrepancy between the two methods was found, suggesting further investigation.

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Analysis of conductive olfactory dysfunction using computational fluid dynamics

PLoS ONE ◽

10.1371/journal.pone.0262579 ◽

2022 ◽

Vol 17 (1) ◽

pp. e0262579

Author(s):

Youji Asama ◽

Akiko Furutani ◽

Masato Fujioka ◽

Hiroyuki Ozawa ◽

Satoshi Takei ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Maximum Flow ◽

Olfactory Dysfunction ◽

Mouth Breathing ◽

Respiratory Physiology ◽

Research Assessment ◽

Nasal Breathing ◽

Olfactory Cleft ◽

Scan Data

Conductive olfactory dysfunction (COD) is caused by an obstruction in the nasal cavity and is characterized by changeable olfaction. COD can occur even when the olfactory cleft is anatomically normal, and therefore, the cause in these cases remains unclear. Herein, we used computational fluid dynamics to examine olfactory cleft airflow with a retrospective cohort study utilizing the cone beam computed tomography scan data of COD patients. By measuring nasal–nasopharynx pressure at maximum flow, we established a cut-off value at which nasal breathing can be differentiated from combined mouth breathing in COD patients. We found that increased nasal resistance led to mouth breathing and that the velocity and flow rate in the olfactory cleft at maximum flow were significantly reduced in COD patients with nasal breathing only compared to healthy olfactory subjects. In addition, we performed a detailed analysis of common morphological abnormalities associated with concha bullosa. Our study provides novel insights into the causes of COD, and therefore, it has important implications for surgical planning of COD, sleep apnea research, assessment of adenoid hyperplasia in children, and sports respiratory physiology.

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An Overview of Computational Fluid Dynamics Preoperative Analysis of the Nasal Airway

Facial Plastic Surgery ◽

10.1055/s-0041-1722956 ◽

2021 ◽

Author(s):

Rui Xavier ◽

Dirk-Jan Menger ◽

Henrique Cyrne de Carvalho ◽

Jorge Spratley

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Surgical Techniques ◽

Virtual Surgery ◽

Nasal Airway ◽

Cfd Analysis ◽

Nasal Airflow ◽

Nasal Breathing ◽

Objective Measurements ◽

Patient Reported

AbstractEvaluation of the nasal airway is crucial for every patient with symptoms of nasal obstruction as well as for every patient with other nasal symptoms. This assessment of the nasal airway comprises clinical examination together with imaging studies, with the correlation between findings of this evaluation and symptoms reported by the patient being based on the experience of the surgeon. Measuring nasal airway resistance or nasal airflow can provide additional data regarding the nasal airway, but the benefit of these objective measurements is limited due to their lack of correlation with patient-reported evaluation of nasal breathing. Computational fluid dynamics (CFD) has emerged as a valuable tool to assess the nasal airway, as it provides objective measurements that correlate with patient-reported evaluation of nasal breathing. CFD is able to evaluate nasal airflow and measure variables such as heat transfer or nasal wall shear stress, which seem to reflect the activity of the nasal trigeminal sensitive endings that provide sensation of nasal breathing. Furthermore, CFD has the unique capacity of making airway analysis of virtual surgery, predicting airflow changes after trial virtual modifications of the nasal airway. Thereby, CFD can assist the surgeon in deciding surgery and selecting the surgical techniques that better address the features of each specific nose. CFD has thus become a trend in nasal airflow assessment, providing reliable results that have been validated for analyzing airflow in the human nasal cavity. All these features make CFD analysis a mainstay in the armamentarium of the nasal surgeon. CFD analysis may become the gold standard for preoperative assessment of the nasal airway.

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Fibrous and Spherical Particle Transport and Deposition in the Human Nasal Airway: A Computational Fluid Dynamics Model

Volume 1: Symposia, Parts A, B and C ◽

10.1115/fedsm2009-78204 ◽

2009 ◽

Author(s):

Kevin T. Shanley ◽

Goodarz Ahmadi ◽

Philip K. Hopke ◽

Yung-Sung Cheng

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Particulate Matter ◽

Particle Tracking ◽

Full Range ◽

Spherical Particles ◽

Lagrangian Particle Tracking ◽

Nasal Breathing ◽

Lagrangian Particle

As the interface between the human respiratory system and the environment, the nose plays many vital roles. Not the least of which is filter. Resulting from numerous natural and anthropogenic processes, particulate matter becomes airborne. Should particulate matter reach the lower portions of the respiratory tract, a host of maladies may occur. In an attempt to further understand the physics behind particulate matter transitioning from the environment into humans a computational model has been developed to predict the efficiency with which human noses can remove particles before they reach the lungs. To this end computational fluid dynamics and Lagrangian particle tracking simulations have been run to gather information on the deposition behavior of both fibrous and spherical particles. MRI data was collected from the left and right passages of a 181.6 cm, 120.2 kg, human male. The two passages were constructed into separate computational volumes consisting of approximately 950,000 unstructured tetrahedral cells each. A steady laminar flow model was used to simulate the inhalation portion of a human breathing cycle. Volumetric flow rates were varied to represent the full range of human nasal breathing. General agreement was shared quantitatively and qualitatively with previously published in vitro studies on other nasal models. Lagrangian particle tracking was performed for varying sizes of fibrous and spherical particles. Deposition efficiency was shown to increase with fiber aspect ratio, particle size, and flow rate. Anatomy was also identified as effecting deposition.

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