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.

Three-dimensional analysis of anchored wall with concrete bearing pads

2020 ◽  
Vol 18 (6) ◽  
pp. 1469-1486
Author(s):  
Hamed Arefizadeh ◽  
Hadi Shahir
Keyword(s):  
Design Methodology ◽  
Three Dimensional ◽  
Bending Moments ◽  
Dimensional Model ◽  
Discrete Elements ◽  
Three Dimensional Model ◽  
Content Type ◽  
Finite Element Software ◽  
Internal Forces ◽  
Soldier Pile

Purpose Anchorage with concrete bearing pad is commonly used in Iran for stabilization of excavations because of the ease of construction, less costs and less time consumption than the soldier pile method. In this method, a wall facing which includes the concrete bearing pads at the location of the anchors and a shotcrete layer between the bearing pads is constructed parallel to the excavation operation similar to the nailing method. Design/methodology/approach In this paper, using the finite element software Abaqus, a three-dimensional model of the above-mentioned type of wall is constructed, and the effect of spacing and size of bearing pads on the wall behavior is discussed. Findings According to the obtained results, the size of the concrete bearing pads has little effect on wall deformations, but the internal forces and bending moments developed in the shotcrete layer between the bearing pads are greatly influenced by the bearing pads dimensions and spacing. Originality/value Owing to the discrete elements of the wall facing, the behavior of this system is completely three-dimensional.

Stakeholder power and corporate social performance

2014 ◽  
Vol 14 (3) ◽  
pp. 363-381 ◽  
Author(s):  
Béchir Ben Lahouel ◽  
Jean-Marie Peretti ◽  
David Autissier
Keyword(s):  
Stakeholder Theory ◽  
Corporate Social Performance ◽  
Social Performance ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Content Type ◽  
Strategic Posture ◽  
Corporate Social ◽  
The Relationship

Purpose – This paper aims to explore the power of one of the primary organizational stakeholders (shareholders) in the development of a corporate social performance (CSP) score. Few research works in the CSP empirical literature have studied the relationship between stakeholder power and CSP. Design/methodology/approach – Stakeholder theory is used as a theoretical framework to explain how shareholder voting power can influence the CSP level of French publicly listed companies. Stakeholder theory is tested through the operationalization of Ullmann’s (1985) three-dimensional model. Hypotheses related to shareholder voting power, strategic posture and financial performance are formulated through a literature review. A Data Envelopment Analysis approach was presented as a strong tool to measure CSP level. Multiple linear regressions were undertaken to test the hypotheses in a sample of 129 French companies between 2006 and 2007. Findings – The results indicate that companies with dispersed ownership and high proportion of institutional shareholders record a high score of CSP. Strategic posture measured by the implementation of environmental certification standard was positively and significantly related to CSP. Financial performance does not affect significantly the level of CSP. Originality/value – This paper is the first to empirically analyse the relationship between Ullmann’s three-dimensional model and CSP level in the French context. It offers to managers a better understanding of the power that certain stakeholders can use to acquire satisfaction.

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.

RESEARCH OF SEPARATION GRADIENT AEROSOL TECHNOLOGIES FOR INTENSIFICATION OF HEAT AND MASS TRANSFER PROCESSES IN SYSTEMS OF HIGHLY TURBULENT DISPERSED BIPHASIC FLOWS. DEVELOPMENT OF SHIP SYSTEM FOR AIR FURIFICATION FROM DROPLET MOISTURE

2019 ◽  
pp. 70-85
Author(s):  
Zhou Pengfei ◽  
Sergiy Ryzhkov
Keyword(s):  
Gas Dynamics ◽  
Static Pressure ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Air Purification ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Flow Rates ◽  
Transfer Processes ◽  
Mass Transfer Processes

The study of gas dynamics and deposition coefficients of the separating profile has been performed. The three-dimensional model of working channels of the ship systems for air purification from droplet moisture is developed. The distribution of velocity, static pressure, dynamic pressure, kinetic energy of turbulence, and deposition coefficients for the flow rates of 5, 10, 15, 20 m/s in separating profiles with the radii of 5, 10, 15, 20, 25 mm. The droplet moisture deposition coefficient is 99.9 %. Designs of the ship systems for air purification from droplet moisture are developed for the air flow ranging from 20 to 2000 m3/hour.

On the Design of Two EAHE Assemblies with Four Ducts

2017 ◽  
Vol 372 ◽  
pp. 31-39 ◽  
Author(s):  
R.S. Brum ◽  
M.K. Rodrigues ◽  
J.V.A. Ramalho ◽  
Luiz Alberto Oliveira Rocha ◽  
Liércio André Isoldi ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
Design Method ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Constructal Design

This article applies the constructal design method to analyze how to improve the thermal performance of earth-air heat exchangers (EAHE) composed by four ducts. The paper evaluates two types of arrangements for which the centers of the ducts take the shape of rectangles and diamonds. Under volumetric constraints, the vertical Sv and horizontal Sh spacings between the ducts are left free to vary. The objective is to maximize the magnitude of the EAHE instantaneous thermal potential P which is an average of the differences between the temperatures at the ducts outlets and inlets at any instant of time. The temperature fields are computed through numerical simulations, adopting a verified and validated three-dimensional model. Among the results, this work shows how the design can raise by 11% the annual thermal efficiency of the EAHE.

Contribution of the three-dimensional model to the reliability allocation of multiphase systems

2019 ◽  
Vol 36 (7) ◽  
pp. 1038-1052
Author(s):  
Saadia Saadi ◽  
Mébarek Djebabra ◽  
Ounsa Roudies ◽  
Wafa Boulagouas
Keyword(s):  
Process Analysis ◽  
Functional Dependence ◽  
Three Dimensional ◽  
Implementation Process ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Reliability Allocation ◽  
Content Type ◽  
Multiphase Systems ◽  
New Formulation

Purpose The purpose of this paper is to deal with the allocation requirements of the dependability of the multiphase systems. Design/methodology/approach It consists of a proposal for a combined methodology based on the simultaneous use of decomposition systems and reliability allocation method. Findings In the developed methodology, the authors use the principles of risk assessment and propose a new formulation of weight allowance with reference to the structural‒functional dependence. Practical implications The suggested methodology provides invaluable help to implementation process analysis. Originality/value The adopted allocation approach is based on the use of a three-dimensional model: temporal, structural and functional decomposition of systems.

scholarly journals The fluid dynamics of canine olfaction: unique nasal airflow patterns as an explanation of macrosmia

2009 ◽  
Vol 7 (47) ◽  
pp. 933-943 ◽  
Author(s):  
Brent A. Craven ◽  
Eric G. Paterson ◽  
Gary S. Settles
Keyword(s):  
Fluid Dynamics ◽  
Nasal Cavity ◽  
Receptor Gene ◽  
Three Dimensional ◽  
Dynamics Simulation ◽  
Airflow Rate ◽  
Gene Repertoire ◽  
Nasal Airflow ◽  
Three Dimensional Model ◽  
Odour Source

The canine nasal cavity contains hundreds of millions of sensory neurons, located in the olfactory epithelium that lines convoluted nasal turbinates recessed in the rear of the nose. Traditional explanations for canine olfactory acuity, which include large sensory organ size and receptor gene repertoire, overlook the fluid dynamics of odorant transport during sniffing. But odorant transport to the sensory part of the nose is the first critical step in olfaction. Here we report new experimental data on canine sniffing and demonstrate allometric scaling of sniff frequency, inspiratory airflow rate and tidal volume with body mass. Next, a computational fluid dynamics simulation of airflow in an anatomically accurate three-dimensional model of the canine nasal cavity, reconstructed from high-resolution magnetic resonance imaging scans, reveals that, during sniffing, spatially separate odour samples are acquired by each nostril that may be used for bilateral stimulus intensity comparison and odour source localization. Inside the nose, the computation shows that a unique nasal airflow pattern develops during sniffing, which is optimized for odorant transport to the olfactory part of the nose. These results contrast sharply with nasal airflow in the human. We propose that mammalian olfactory function and acuity may largely depend on odorant transport by nasal airflow patterns resulting from either the presence of a highly developed olfactory recess (in macrosmats such as the canine) or the lack of one (in microsmats including humans).

Three-Dimensional Model for Virtual Surgical Simulation, during Complex Skull Base Surgery and Aneurysm Surgery

Skull Base ◽  
2008 ◽  
Vol 18 (S 01) ◽  
Author(s):  
Akio Morita ◽  
Toshikazu Kimura ◽  
Shigeo Sora ◽  
Kengo Nishimura ◽  
Hisayuki Sugiyama ◽  
...  
Keyword(s):  
Skull Base ◽  
Surgical Simulation ◽  
Skull Base Surgery ◽  
Three Dimensional ◽  
Aneurysm Surgery ◽  
Dimensional Model ◽  
Three Dimensional Model
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