scholarly journals Nasal airflow of patient with septal deviation and allergy rhinitis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zi Fen Lim ◽  
Parvathy Rajendran ◽  
Muhamad Yusri Musa ◽  
Chih Fang Lee
Keyword(s):  
Middle Turbinate ◽  
Three Dimensional ◽  
Septal Deviation ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Interactive Application ◽  
Analysis System

AbstractA numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics. Accordingly, computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained. The three-dimensional (3D) nasal model was designed using InVesalius 3.0, which was then imported to (computer aided 3D interactive application) CATIA V5 for modification, and finally to analysis system (ANSYS) flow oriented logistics upgrade for enterprise networks (FLUENT) to obtain the numerical solution. The velocity contours of the cross-sectional area were analyzed on four main surfaces: the vestibule, nasal valve, middle turbinate, and nasopharynx. The pressure and velocity characteristics were assessed at both laminar and turbulent mass flow rates for both the standardized and the patient’s model nasal cavity. The developed model of the patient is approximately half the size of the standardized model; hence, its velocity was approximately two times more than that of the standardized model.

Influence of airflow dynamics on vortices in the human nasal cavity

2019 ◽  
Vol 36 (9) ◽  
pp. 3164-3179
Author(s):  
Punjan Dohare ◽  
Amol P. Bhondekar ◽  
Anupma Sharma ◽  
C. Ghanshyam
Keyword(s):  
Numerical Simulations ◽  
Nasal Cavity ◽  
Three Dimensional ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Flow Rates ◽  
Content Type ◽  
Human Nose

Purpose The purpose of this paper is to understand the effect of airflow dynamics on vortices for different flow rates using the human nose three-dimensional model. Design/methodology/approach Olfaction originates with air particles travelling from an external environment to the upper segment of the human nose. This phenomenon is generally understood by using the nasal airflow dynamics, which enhances the olfaction by creating the vortices in the human nose. An anatomical three-dimensional model of the human nasal cavity from computed tomography (CT) scan images using the MIMICS software (Materialise, USA) was developed in this study. Grid independence test was performed through volume flow rate, pressure drop from nostrils and septum and average velocity near the nasal valve region using a four computational mesh model. Computational fluid dynamics (CFD) was used to examine the flow pattern and influence of airflow dynamics on vortices in the nasal cavity. Numerical simulations were conducted for the flow rates of 7.5, 10, 15 and 20 L/min using numerical finite volume methods. Findings At coronal cross-sections, dissimilar nasal airflow patterns were observed for 7.5, 10, 15 and 20 L/min rate of fluid flow in the human nasal cavity. Vortices that are found at the boundaries with minimum velocity creates deceleration zone in the nose vestibule region, which is accompanied by flow segregation. Maximum vortices were observed in the nasal valve region and the posterior end of the turbinate region, which involves mixing and recirculation and is responsible for enhancing the smelling process. Practical implications The proposed analysis is applicable to design the sensor chamber for electronic noses. Originality/value In this paper, the influence of airflow dynamics on vortices in the human nasal cavity is discussed through numerical simulations.

scholarly journals Effectiveness of endoscopic intranasal incision reduction for nasal fractures

2021 ◽  
Author(s):  
Shu Yan ◽  
Yan Jiang ◽  
Yan Wang ◽  
Kaixuan Chen ◽  
Xudong Yan ◽  
...  
Keyword(s):  
Intraoperative Complications ◽  
Three Dimensional ◽  
Junior Doctors ◽  
3D Ct ◽  
Nasal Airflow ◽  
Temporal Window ◽  
Cross Sectional ◽  
Frontal Process ◽  
Bone Fragments ◽  
Nasal Fractures

Abstract Purpose To report our experience using endoscopic intranasal incision reduction (EIIR) for nasal fractures and to assess effectiveness of the method. Methods 30 patients who underwent EIIR were retrospectively analysed. All the patients were examined by three-dimensional computed tomography (3D CT), acoustic rhinometry and rhinomanometry, preoperatively and postoperatively at 1 month. The visual analogue scale (VAS) was used to assess the preoperative aesthetics and nasal airflow satisfaction and at 1, 3 and 6 months postoperatively. VAS aesthetic satisfaction was also scored by two junior doctors. Results 3D CT showed that the fracture fragments fitted well in 30 patients postoperatively at 1 month. VAS aesthetics and nasal airflow scores were significantly improved postoperatively at 1, 3 and 6 months compared with preoperative scores (P < 0.01). The VAS aesthetic scores from the two surgeons were also significantly improved (P < 0.01). The minimal cross-sectional area increased from 0.39 ± 0.13 to 0.64 ± 0.13 (P < 0.001), the nasal volume increased from 4.65 ± 0.86 to 6.37 ± 0.94 (P < 0.001) and the total inspiratory airway resistance of the bilateral nasal cavity median decreased from 0.467 Pa/mL/s to 0.193 Pa/mL/s (P < 0.001). There were no technique-related intraoperative complications. Conclusion EIIR was a practical choice, and the aesthetics and nasal airflow were significantly improved in patients with overlapped and displaced bone fragments, patients with fractures of the frontal process of the maxilla (FFPM), patients who underwent failed CR and patients beyond the optimal temporal window.

The Effect of Closed Septorhinoplasty on Nasal Functions and on External and Internal Nasal Valves: A Prospective Study

2017 ◽  
Vol 31 (5) ◽  
pp. 323-327 ◽  
Author(s):  
Giancarlo Pecorari ◽  
Giuseppe Riva ◽  
Francesca Antonella Bianchi ◽  
Giovanni Cavallo ◽  
Francesca Revello ◽  
...  
Keyword(s):  
Prospective Study ◽  
Nasal Obstruction ◽  
Laser Scanning ◽  
Soft Tissues ◽  
Statistical Significance ◽  
Three Dimensional ◽  
Subjective Assessment ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Objective Reduction

Background Because nasal function and shape are so closely intertwined, quantitative assessments can better define their relationship and how they are affected by septorhinoplasty. Objective The aim of this prospective study was to perform an analysis of the nasal airflow resistances and a three-dimensional (3D) evaluation of the soft-tissue changes after closed septorhinoplasty. Methods Before surgery (TO) and 6 months after closed septorhinoplasty (Tl), 30 patients underwent symptoms evaluation by means of the Italian version of the Nasal Obstruction Symptom Evaluation scale, endoscopic fiberoptic nasal examination, and visual analog scale for subjective assessment of nasal obstruction. Nasal airflow resistances were investigated with active anterior active rhinomanometry. A 3D laser scanner was used to evaluate facial soft-tissues, with specific nasal points and angles. Results Subjective nasal obstruction decreased. Anterior active rhinomanometry demonstrated a reduction in total inspiratory and expiratory resistances between T0 and T1 but without statistical significance. The significance was still absent after decongestion, excluding turbinate hypertrophy as a cause of failed objective amelioration of nasal resistance. Facial laser scanning showed statistically significant reduction of the superior nasal width and superior alar angle, and a weak negative correlation between the superior alar angle and nasal resistances. Conclusion The absence of objective reduction of nasal airflow resistances could be the result of concurrent surgery on nasal septum and nasal valve. In particular, the ameliorating effect on nasal airflow resistances is counterbalanced by the worsening effect of the narrowing of nasal valve.

scholarly journals The Influence of Flow Rate on the Wake in a Centrifugal Impeller

1982 ◽  
Author(s):  
M. W. Johnson ◽  
J. Moore
Keyword(s):  
Flow Rate ◽  
Incidence Angle ◽  
Three Dimensional ◽  
Stagnation Pressure ◽  
Centrifugal Impeller ◽  
Suction Surface ◽  
Cross Sectional ◽  
Flow Rates ◽  
Pressure Losses ◽  
Compressor Impeller

Three-dimensional flows and their influence on the stagnation pressure losses in a centrifugal compressor impeller have been studied. All 3 mutally perpendicular components of relative velocity and stagnation pressure on 5 cross-sectional planes, between the inlet and outlet of a 1 m dia shrouded impeller running at 500 rpm were measured. Comparisons were made between results for a flow rate corresponding to nearly zero incidence angle and two other flows, with increased and reduced flow rates. These detailed measurements show how the position of separation of the shroud boundary layer moved downstream and the wake’s size decreased, as the flow rate was increased. The wake’s location, at the outlet of the impeller, was also observed to move from the suction surface at the lowest flow rate, to the shroud at higher flow rates.

Analysis of the Mixing Plane Interface Between Stator and Rotor of a Transonic Axial Turbine Stage

2000 ◽  
Author(s):  
P. Giangiacomo ◽  
V. Michelassi ◽  
F. Martelli
Keyword(s):  
Mass Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Turbine Stage ◽  
Flow Rates ◽  
Tip Leakage ◽  
Mass Flow Rates ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Rotor Mass

A three-dimensional transonic turbine stage is computed by means of a numerical simulation tool. The simulation accounts for the coolant ejection from the stator blade and for the tip leakage of the rotor blade. The stator and rotor rows interact via a mixing plane, which allows the stage to be computed in a steady manner. The analysis is focused on the matching of the stator and rotor mass flow rates. The computations proved that the mixing plane approach allows the stator and rotor mass flow rates to be balanced with a careful choice of the stator-rotor static pressure interface. At the same time, the pitch averaged distribution of the transported quantities at the interface for the stator and rotor may differ slightly, together with the value of the static pressure at the hub.

scholarly journals The complexities of nasal airflow: theory and practice

2019 ◽  
Vol 127 (5) ◽  
pp. 1215-1223 ◽  
Author(s):  
Graham O’Neill ◽  
Neil Samuel Tolley
Keyword(s):  
Theory And Practice ◽  
Poor Correlation ◽  
Airflow Rate ◽  
Nasal Resistance ◽  
Flow Limitation ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Pressure Flow ◽  
Valve Area

The objective of this study was to investigate the effects of nasal valve area, valve stiffness, and turbinate region cross-sectional area on airflow rate, nasal resistance, flow limitation, and inspiratory “hysteresis” by the use of a mathematical model of nasal airflow. The model of O’Neill and Tolley ( Clin Otolaryngol Allied Sci 13: 273–277, 1988) describing the effects of valve area and stiffness on the nasal pressure-flow relationship was improved by the incorporation of additional terms involving 1) airflow through the turbinate region, 2) the dependence of the flow coefficients for the valve and turbinate region on the Reynolds number, and 3) effects of unsteady flow. The model was found to provide a good fit for normal values for nasal resistance and for pressure-flow curves reported in the literature for both congested and decongested states. Also, by showing the relative contribution of the nasal valve and turbinate region to nasal resistance, the model sheds light in explaining the generally poor correlation between nasal resistance measurements and the results from acoustic rhinometry. Furthermore, by proposing different flow conditions for the acceleration and deceleration phases of inspiration, the model produces an inspiratory loop (commonly referred to as hysteresis) consistent with those reported in the literature. With simulation of nasal flaring, the magnitude of the loop, the nasal resistance, and flow limitation all show change similar to that observed in the experimental results. NEW & NOTEWORTHY The present model provides considerable insight into some difficult conundrums in both clinical and technical aspects of nasal airflow. Also, the description of nasal airflow mechanics based on the Hagen–Poiseuille equation and Reynolds laminar-turbulent transition in long straight tubes, which has figured prominently in medical textbooks and journal articles for many years, is shown to be seriously in error at a fundamental level.

scholarly journals Multi-branching three-dimensional flow with substantial changes in vessel shapes

2008 ◽  
Vol 614 ◽  
pp. 329-354 ◽  
Author(s):  
R. I. BOWLES ◽  
N. C. OVENDEN ◽  
F. T. SMITH
Keyword(s):  
Three Dimensional ◽  
Longitudinal Vortex ◽  
Cross Sectional ◽  
Flow Rates ◽  
Relative Flow Rate ◽  
Wide Range ◽  
Flow Through ◽  
Sectional Shape ◽  
Area Expansion ◽  
Reversed Motion

This theoretical investigation of steady fluid flow through a rigid three-dimensional branching geometry is motivated by applications to haemodynamics in the brain especially, while the flow through a tube with a blockage or through a collapsed tube provides another motivation with a biomedical background. Three-dimensional motion without symmetry is addressed through one mother vessel to two or several daughters. A comparatively long axial length scale of the geometry leads to a longitudinal vortex system providing a slender-flow model for the complete mother-and-daughters flow response. Computational studies and subsequent analysis, along with comparisons, are presented. The relative flow rate varies in terms of an effective Reynolds number dependence, allowing a wide range of flow rates to be examined theoretically; also any rigid cross-sectional shape and ratio of cross-sectional area expansion or contraction from the mother vessel to the daughters can be accommodated in principle in both the computations and the analysis. Swirl production with substantial crossflows is found. The analysis shows that close to any carina (the ridge separating daughter vessels) or carinas at a branch junction either forward or reversed motion can be observed locally at the saddle point even though the bulk of the motion is driven forward into the daughters. The local forward or reversed motion is controlled, however, by global properties of the geometry and incident conditions, a feature which applies to any of the flow rates examined.

scholarly journals The effect of decongestion on nasal airway patency and airflow

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qiwei Xiao ◽  
Alister J. Bates ◽  
Raul Cetto ◽  
Denis J. Doorly
Keyword(s):  
Nasal Airway ◽  
Nasal Resistance ◽  
Nasal Airflow ◽  
Cross Sectional ◽  
Airway Patency ◽  
Flow Rates ◽  
High Resolution Mri ◽  
Nasal Anatomy ◽  
Before And After ◽  
Flow Through

AbstractNasal decongestant reduces blood flow to the nasal turbinates, reducing tissue volume and increasing nasal airway patency. This study maps the changes in nasal anatomy and measures how these changes affect nasal resistance, flow partitioning between superior and inferior cavity, flow patterns and wall shear stress. High-resolution MRI was applied to capture nasal anatomy in 10 healthy subjects before and after application of a topical decongestant. Computational fluid dynamics simulated nasal airflow at steady inspiratory flow rates of 15 L.min$$^{-1}$$ - 1 and 30 L.min$$^{-1}$$ - 1 . The results show decongestion mainly increases the cross-sectional area in the turbinate region and SAVR is reduced (median approximately 40$$\%$$ % reduction) in middle and lower parts of the cavity. Decongestion reduces nasal resistance by 50$$\%$$ % on average, while in the posterior cavity, nasal resistance decreases by a median factor of approximately 3 after decongestion. We also find decongestant regularises nasal airflow and alters the partitioning of flow, significantly decreasing flow through the superior portions of the nasal cavity. By comparing nasal anatomies and airflow in their normal state with that when pharmacologically decongested, this study provides data for a broad range of anatomy and airflow conditions, which may help characterize the extent of nasal variability.

Study of the Flow Pattern in Compact Manifold Type Junctions by LDA

1987 ◽  
Vol 109 (4) ◽  
pp. 452-458 ◽  
Author(s):  
R. Sierens ◽  
P. Snauwaert
Keyword(s):  
Compact Manifold ◽  
Laser Doppler Anemometry ◽  
Three Dimensional ◽  
Velocity Measurements ◽  
Flow Rates ◽  
Pressure Distributions ◽  
Mass Flow Rates ◽  
Loss Coefficients ◽  
Flow Configurations ◽  
Pressure And Velocity Measurements

In this paper pressure and velocity measurements on two theoretical compact manifold type junctions (compact pulse converters) under steady-state conditions are described. The velocity measurements are done with Laser-Doppler anemometry (LDA). The pressure distributions and the velocity profiles for different flow configurations and different mass flow rates are presented. These results are used for calculation of loss coefficients and for comparison with a numerical algorithm for simulating the three dimensional turbulent quasi-steady flow in compact manifold type junctions.

Internal Geometry and External Wall Effects on Fluidic Oscillator Behavior

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Gabrielle C. Claus ◽  
Andrew Hatton ◽  
Brian T. Bohan ◽  
Marc D. Polanka
Keyword(s):  
Area Ratio ◽  
Wall Effects ◽  
Cross Sectional ◽  
Flow Rates ◽  
Co2 Gas ◽  
Fluidic Oscillator ◽  
Internal Geometry ◽  
Exit Nozzle ◽  
Mass Flow Rates ◽  
Jet Oscillation

Abstract This study quantified the correlation of internal geometry (including Coanda effects) and external walls on oscillation frequency for a fluidic oscillator that was tested for a variety of mass flow rates using CO2 gas. The oscillator designs were modified by altering the aspect ratio (AR) with respect to the exit nozzle and changing the cross-sectional area ratio (MR) between the exit throat and power nozzle. The AR and cross-sectional MR were shown to be correlated with frequency. External walls parallel to each other and perpendicular to the oscillator exit throat were added at varying separation distances to observe how they affected the jet oscillation angle and frequency. By increasing the convexity of the exit throat, Coanda effects were about three times more effective in increasing the oscillation angle compared to wall effects. The internal geometry effects were combined by nondimensional analysis to find a function for predicting the frequency of an oscillator in terms of aspect and area ratios. The function showed that the oscillators converged to a single Strouhal number of 0.016.

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