scholarly journals A preoperative predictive study of advantages of airway changes after maxillomandibular advancement surgery using computational fluid dynamics analysis

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255973
Author(s):  
Kanako Yamagata ◽  
Keiji Shinozuka ◽  
Shouhei Ogisawa ◽  
Akio Himejima ◽  
Hiroaki Azaki ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Preoperative Prediction ◽  
Maxillomandibular Advancement ◽  
Computational Mesh ◽  
Computational Fluid Dynamics Analysis ◽  
Simulation Results ◽  
Predicted Values ◽  
The Right ◽  
Dynamics Models

The purpose of this study was to develop a simulation approach for predicting maxillomandibular advancement-induced airway changes using computational fluid dynamics. Eight patients with jaw deformities who underwent maxillomandibular advancement and genioglossus advancement surgery were included in this study. Computed tomography scans and rhinomanometric readings were performed both preoperatively and postoperatively. Computational fluid dynamics models were created, and airflow simulations were performed using computational fluid dynamics software; the preferable number of computational mesh points was at least 10 million cells. The results for the right and left nares, including simulation and postoperative measurements, were qualitatively consistent, and surgery reduced airflow pressure loss. Geometry prediction simulation results were qualitatively consistent with the postoperative stereolithography data and postoperative simulation results. Simulations were performed with either the right or left naris blocked, and the predicted values were similar to those found clinically. In addition, geometry prediction simulation results were qualitatively consistent with the postoperative stereolithography data and postoperative simulation results. These findings suggest that geometry prediction simulation facilitates the preoperative prediction of the postoperative structural outcome.

Computational Fluid Dynamics Analysis of Two Parallel Rectangular Jets Using OpenFOAM

2016 ◽  
Author(s):  
Han Li ◽  
Huhu Wang ◽  
Yassin A. Hassan ◽  
N. K. Anand
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbulent Flow ◽  
Stokes Equations ◽  
Laser Doppler Anemometry ◽  
Physical Models ◽  
Shear Stresses ◽  
Turbulence Characteristic ◽  
Computational Fluid Dynamics Analysis ◽  
Simulation Results

Two or multiple parallel jets are an important shear flow that widely existing in many industrial applications. The interaction between turbulence jets enables fast and thorough mixing of two fluids. The mixing feature of parallel jets has many engineering applications, such as, in Generation IV conceptual nuclear reactors, the coolants merge in upper or lower plenum after passing through the reactor core. While study of parallel jets mixing phenomenon, numerical experiments such as Computational Fluid Dynamics (CFD) simulations are extensively incorporated. Validation of varied turbulent models is of importance to make sure that the numerical results could be trusted and served as a guideline further design purpose. Many commercial CFD packages in the market such as FLUENT and Star CCM+ can provide the ability to simulate turbulent flow with predefined turbulence model, however, such commercial solvers may lack the flexibility that allow users build their own models for R&D purpose. The existing solvers in OpenFOAM are developed to fulfill both academic and industrial needs by achieving large-scale computational capability with a variety of physical models. Moreover, as an open source CFD toolbox, OpenFOAM grants users full control of the source code with complete freedom of customization. The purpose of this study is to perform CFD simulation using OpenFOAM for two submerged parallel jets issuing from two rectangular channels. Fully hexahedron multi-density mesh is generated using blockMesh utility to ensure velocity gradients are properly evaluated. A generalized-multi-grid solver is used to enhance convergence. Based on Reynolds-Averaged Navier-Stokes Equations (RANS), the realizable k-ε and k-ε shear stress transport (SST) are selected to model turbulent flow. Steady state Finite Volume solver simpleFoam is used to perform the simulation. In addition, data from experiments run in Thermal-Hydraulic Lab at Texas A&M University using particle image velocity (PIV) and Laser Doppler Anemometry (LDA) methods are considered in order to compare and validate simulation results. A number of turbulence characteristic such as mean velocities, turbulent intensities, z-component vorticity were compared with experiments. It was found that for stream-wise mean velocity profile as well as shear stresses, the realizable k-ε model exhibits a good agreement with experimental data. However, velocity fluctuation and turbulence intensities, simulation results showed a certain discrepancy.

COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF FABRICATED MICRONOZZLE FOR SUPERSONIC PARTICLE DEPOSITION

2010 ◽  
Vol 17 (01) ◽  
pp. 45-49
Author(s):  
KYUBONG JUNG ◽  
WOOJIN SONG ◽  
DOO-MAN CHUN ◽  
JUN-CHEOL YEO ◽  
MIN-SAENG KIM ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Deposition ◽  
Room Temperature ◽  
Flow Analysis ◽  
Dynamics Analysis ◽  
Nanoparticle Deposition ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

A micronozzle was applied in nanoparticle deposition system (NPDS) for supersonic deposition. To determine whether suitable behavior of supersonic fluid can be produced or not, computational fluid dynamics (CFD) flow analysis was used. Ni particles were successfully deposited using the fabricated micronozzle in NPDS at room temperature. It was found that shorter micronozzle with larger side profile deposits wide and thick film compared to the deposition using long micronozzle with smaller side profile. These experimental results agree with the simulation results.

scholarly journals Aerodynamic Analysis of Spoiler at Varying Speeds and Angles

2021 ◽  
Vol 9 (11) ◽  
pp. 526-535
Author(s):  
Manas Metar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Analysis ◽  
Wake Region ◽  
Aerodynamic Analysis ◽  
Pressure Drag ◽  
High Speeds ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

Abstract: Spoilers have been there in practice since years for the purpose of improving aerodynamics of a car. The pressure drag created at the end of the vehicle, referred to as wake region affects handling of the vehicle. This could be hazardous for the cars at high speeds. By adding a spoiler to the rear of the car reduces that pressure drag and the enhanced downforce helps in better traction. The paper presents aerodynamic analysis of a spoiler through Computational Fluid Dynamics analysis. The spoiler is designed using Onshape software and analyzed through SIMSCALE software. The simulation is carried out by changing angles of attack and velocities. The simulation results of downforce and drag are compared on the basis of analytical method. Keywords: Designing a spoiler, Design and analysis of spoiler, Aerodynamics of spoiler, Aerodynamic analysis of spoiler, Computational fluid dynamics, CFD analysis, CFD analysis of spoiler, Spoiler at variable angles, Types of spoilers, Analytical aerodynamic analysis.

Computational Fluid Dynamics Study of a Small Vertical Axis Wind Turbine with Ball-Shaped Blades

2011 ◽  
Vol 347-353 ◽  
pp. 319-322
Author(s):  
Zu Peng Zhou ◽  
Qiu Yun Mo ◽  
Zhi Peng Lei
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Power Efficiency ◽  
Vertical Axis ◽  
Curvature Radius ◽  
Dynamics Analysis ◽  
Vertical Axis Wind Turbine ◽  
Computational Fluid Dynamics Analysis ◽  
Simulation Results

The computational fluid dynamics analysis of a small vertical axis wind turbine with ball-shaped blades has been done in this paper. First, a three-dimensioned model of the wind turbine with the ball-shaped blades has been constructed by using the software of FLUENT 6.3. Then, by giving the size parameters and shape parameters of the blades, the simulation has been done and the corresponding simulation results have been obtained. The contuours of static pressure around the wind blade area has been shown. The simulated model and the results can be used for finding the factors which will affect the power efficiency of this type of wind turbine in the future. Finally, the simulation results of the blade with zero curvature radius and curvature radius of 2 are shown and compared in order to demonstrate the effectiveness of this computational fluid dynamics analysis method. It can be concluded that the blades with curvature of 2 can obtain more toruqe comparing with the zero one and it would be the more suitable option in the blade design.

Effect of the Distance between Guided Needle and Cone Body on Properties of Vortex Spun Yarn

2014 ◽  
Vol 1048 ◽  
pp. 575-578
Author(s):  
Mei Ling Li ◽  
Chong Wen Yu ◽  
Shan Shan Shang
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Pressure Distribution ◽  
Air Flow ◽  
Yarn Quality ◽  
Spun Yarn ◽  
Simulation Results ◽  
Dynamics Models

Effects of the distance between guided needle and cone body on properties of MVS yarns were investigated by numerical simulation. 5 groups of the distance are designed (0.5mm, 1mm, 1.5mm, 2mm and 2.5mm). The 3D computational fluid dynamics models are established to conduct the numerical simulation of the airflow in the nozzle. Through analysis of the characteristics of air flow inside the different nozzles, such as pressure distribution and velocity vectors, the motion of drafted fibers and performances of yarns are discussed. Simulation results show that when the distance is 1.5mm, the airflow state within the nozzle is beneficial to form more open-ends and twist, and the yarn quality would be better.

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