scholarly journals Design of a three-dimensional hand/forearm model to apply computational fluid dynamics

2010 ◽  
Vol 53 (2) ◽  
pp. 436-442 ◽  
Author(s):  
Daniel Almeida Marinho ◽  
Victor Machado Reis ◽  
João Paulo Vilas-Boas ◽  
Francisco Bessone Alves ◽  
Leandro Machado ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Digital Model ◽  
Human Hand ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Perfect Agreement ◽  
Computational Data ◽  
Processing Techniques

The purpose of this study was to develop a three-dimensional digital model of a human hand and forearm to apply Computational Fluid Dynamics to propulsion analysis in swimming. Computer tomography scans of the hand and forearm of an Olympic swimmer were applied. The data were converted, using image processing techniques, into relevant coordinate input, which could be used in Computational Fluid Dynamics software. From that analysis, it was possible to verify an almost perfect agreement between the true human segment and the digital model. This technique could be used as a means to overcome the difficulties in developing a true three-dimensional model of a specific segment of the human body. Additionally, it could be used to improve the use of Computational Fluid Dynamics generally in sports and specifically in swimming studies, decreasing the gap between the experimental and the computational data.

scholarly journals Numerical Simulation of a Propeller-Type Turbine for In-Pipe Installation

2021 ◽  
Vol 83 (1) ◽  
pp. 1-16
Author(s):  
Oscar Darío Monsalve Cifuentes ◽  
Jonathan Graciano Uribe ◽  
Diego Andrés Hincapié Zuluaga
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Hydraulic Efficiency ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Mesh Independence ◽  
Using Data

In this work, a 76 mm diameter propeller-type turbine is numerically investigated using a parametric study and computational fluid dynamics. The three-dimensional model of the turbine is modeled using data available in the bibliography. A mesh independence study is carried out utilizing a tetrahedron-based mesh with inflation layers around the turbine blade and the pipe wall. The best efficiency point is determined by the maximum hydraulic efficiency of 64.46 %, at a flow rate of 9.72x10-3 m3/s , a head drop of 1.76 m, and a mechanical power of 107.83 W. Additionally, the dimensionless distance y+, pressure, and velocity contours are shown.

A three-dimensional model for analyzing the effects of salmon redds on hyporheic exchange and egg pocket habitat

2009 ◽  
Vol 66 (12) ◽  
pp. 2157-2173 ◽  
Author(s):  
Daniele Tonina ◽  
John M. Buffington
Keyword(s):  
Fluid Dynamics ◽  
Hydraulic Conductivity ◽  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Three Dimensional ◽  
Hyporheic Exchange ◽  
Dimensional Model ◽  
Dynamics Model ◽  
Three Dimensional Model ◽  
Channel Hydraulics

A three-dimensional fluid dynamics model is developed to capture the spatial complexity of the effects of salmon redds on channel hydraulics, hyporheic exchange, and egg pocket habitat. We use the model to partition the relative influences of redd topography versus altered hydraulic conductivity (winnowing of fines during spawning) on egg pocket conditions for a simulated pool–riffle channel with a redd placed at the pool tail. Predictions show that altered hydraulic conductivity is the primary factor for enhancing hyporheic velocities and dissolved oxygen content within the egg pocket. Furthermore, the simulations indicate that redds induce hyporheic circulation that is nested within that caused by pool–riffle topography and that spawning-related changes in hyporheic velocities and dissolved oxygen content could create conditions suitable for incubation in locations that otherwise would be unfavorable (reinforcing the notion that salmonids actively modify their environment in ways that may be beneficial to their progeny).

Anatomically based three-dimensional model of airways to simulate flow and particle transport using computational fluid dynamics

2005 ◽  
Vol 98 (3) ◽  
pp. 970-980 ◽  
Author(s):  
Caroline van Ertbruggen ◽  
Charles Hirsch ◽  
Manuel Paiva
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Deposition ◽  
Gas Flow ◽  
Three Dimensional ◽  
Bronchial Tree ◽  
Inspiratory Flow ◽  
Three Dimensional Model ◽  
Viscous Pressure ◽  
Curved Ducts

We have studied gas flow and particle deposition in a realistic three-dimensional (3D) model of the bronchial tree, extending from the trachea to the segmental bronchi (7th airway generation for the most distal ones) using computational fluid dynamics. The model is based on the morphometrical data of Horsfield et al. (Horsfield K, Dart G, Olson DE, Filley GF, and Cumming G. J Appl Physiol 31: 207–217, 1971) and on bronchoscopic and computerized tomography images, which give the spatial 3D orientation of the curved ducts. It incorporates realistic angles of successive branching planes. Steady inspiratory flow varying between 50 and 500 cm3/s was simulated, as well as deposition of spherical aerosol particles (1–7 μm diameter, 1 g/cm3 density). Flow simulations indicated nonfully developed flows in the branches due to their relative short lengths. Velocity flow profiles in the segmental bronchi, taken one diameter downstream of the bifurcation, were distorted compared with the flow in a simple curved tube, and wide patterns of secondary flow fields were observed. Both were due to the asymmetrical 3D configuration of the bifurcating network. Viscous pressure drop in the model was compared with results obtained by Pedley et al. (Pedley TJ, Schroter RC, and Sudlow MF. Respir Physiol 9: 387–405, 1970), which are shown to be a good first approximation. Particle deposition increased with particle size and was minimal for ∼200 cm3/s inspiratory flow, but it was highly heterogeneous for branches of the same generation.

scholarly journals Characterizing the Shearing Stresses within the CDC Biofilm Reactor Using Computational Fluid Dynamics

2021 ◽  
Vol 9 (8) ◽  
pp. 1709
Author(s):  
Erick Johnson ◽  
Theodore Petersen ◽  
Darla M. Goeres
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Critical Factor ◽  
Test Methods ◽  
Standard Test ◽  
Biofilm Reactor ◽  
Shear Stresses ◽  
Three Dimensional Model

Shearing stresses are known to be a critical factor impacting the growth and physiology of biofilms, but the underlying fluid dynamics within biofilm reactors are rarely well characterized and not always considered when a researcher decides which biofilm reactor to use. The CDC biofilm reactor is referenced in validated Standard Test Methods and US EPA guidance documents. The driving fluid dynamics within the CDC biofilm reactor were investigated using computational fluid dynamics. An unsteady, three-dimensional model of the CDC reactor was simulated at a rotation rate of 125 RPM. The reactor showed turbulent structures, with shear stresses averaging near 0.365 ± 0.074 Pa across all 24 coupons. The pressure variation on the coupon surfaces was found to be larger, with a continuous 2–3 Pa amplitude, coinciding with the baffle passage. Computational fluid dynamics was shown to be a powerful tool for defining key fluid dynamic parameters at a high fidelity within the CDC biofilm reactor. The consistency of the shear stresses and pressures and the unsteadiness of the flow within the CDC reactor may help explain its reproducibility in laboratory studies. The computational model will enable researchers to make an informed decision whether the fluid dynamics present in the CDC biofilm reactor are appropriate for their research.

scholarly journals The Effect of Depth on Drag During the Streamlined Glide: A Three-Dimensional CFD Analysis

2012 ◽  
Vol 33 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Maria Novais ◽  
António Silva ◽  
Vishveshwar Mantha ◽  
Rui Ramos ◽  
Abel Rouboa ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Hydrodynamic Drag ◽  
Cfd Analysis ◽  
Three Dimensional Model ◽  
Commercial Code ◽  
Elite Level ◽  
Computation Fluid Dynamic

The Effect of Depth on Drag During the Streamlined Glide: A Three-Dimensional CFD AnalysisThe aim of this study was to analyze the effects of depth on drag during the streamlined glide in swimming using Computational Fluid Dynamics. The Computation Fluid Dynamic analysis consisted of using a three-dimensional mesh of cells that simulates the flow around the considered domain. We used the K-epsilon turbulent model implemented in the commercial code Fluent® and applied it to the flow around a three-dimensional model of an Olympic swimmer. The swimmer was modeled as if he were gliding underwater in a streamlined prone position, with hands overlapping, head between the extended arms, feet together and plantar flexed. Steady-state computational fluid dynamics analyses were performed using the Fluent® code and the drag coefficient and the drag force was calculated for velocities ranging from 1.5 to 2.5 m/s, in increments of 0.50m/s, which represents the velocity range used by club to elite level swimmers during the push-off and glide following a turn. The swimmer model middle line was placed at different water depths between 0 and 1.0 m underwater, in 0.25m increments. Hydrodynamic drag decreased with depth, although after 0.75m values remained almost constant. Water depth seems to have a positive effect on reducing hydrodynamic drag during the gliding. Although increasing depth position could contribute to decrease hydrodynamic drag, this reduction seems to be lower with depth, especially after 0.75 m depth, thus suggesting that possibly performing the underwater gliding more than 0.75 m depth could not be to the benefit of the swimmer.

Numerical Simulation on Solidification of Flow inside an Elliptical Pipe

2015 ◽  
Vol 799-800 ◽  
pp. 751-755
Author(s):  
Lan Li ◽  
Huan Ma ◽  
Feng Qi Si ◽  
Kang Ping Zhu
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Three Dimensional ◽  
Short Axis ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Axis Direction ◽  
Lower Reynolds Number ◽  
Flow Through

The aim of this investigation is to study the characteristics of solidification of flow through an elliptical pipe and to avoid the solidification and blockage in the pipe. A three-dimensional model has been completed using the commercial fluid dynamics code, Fluent. Analyses under different conditions show that different factors affect the characteristics of solidification and heat transfer in the pipe. The lower Reynolds number is or the higher dimensionless wall temperature turns, the thicker the ice layer becomes, which will increase the risk of blockage. The thickness at the long axis direction will grow with the increase of ellipse aspect ratio while it turns out contrary at short axis direction.

A Computational Fluid Dynamics Comparison of Wells Turbine Blades in 2D and 3D Cascade Flow

2002 ◽  
Author(s):  
John Daly ◽  
Patrick Frawley ◽  
Ajit Thakker
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Primary Objective ◽  
Two Dimensional ◽  
Three Dimensional Model ◽  
Wells Turbine ◽  
Cascade Flow ◽  
Cascade Models

This paper deals with the application of Computational Fluid Dynamics (CFD) to the analysis of the aerodynamic characteristics of symmetrical airfoil blades in 2-Dimensional cascade flow. Theoretical two dimensional cascade analyses of Wells Turbines blade profiles have been used in the past to predict the performance of three-dimensional turbines. The use of two-dimensional cascade models is beneficial as it allows the analysis and optimisation of the blade profile with approximately one tenth the computational requirements of a three-dimensional model. The primary objective of this work was to provide further validation of the use of two dimensional cascade models by comparing the computational predictions with traditional theoretical calculation results and also with three-dimensional turbine results. A secondary objective was to use the two dimensional cascade models to better understand the blade interaction effects that occur in the Wells Turbine. The model was used to analyse and compare three different blade profiles at different cascade settings. This paper presents the results of the numerical investigation, the validation of the results and the subsequent analysis.

A three-dimensional model of the fluid dynamics of radio-trail sources

Nature ◽  
1984 ◽  
Vol 310 (5972) ◽  
pp. 33-36 ◽  
Author(s):  
A. G. Williams ◽  
S. F. Gull
Keyword(s):  
Fluid Dynamics ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model

A computational fluid dynamics model of a solid oxide fuel cell

2005 ◽  
Vol 219 (3) ◽  
pp. 159-167 ◽  
Author(s):  
K Sudaprasert ◽  
R P Travis ◽  
R F Martinez-Botas
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Thermal Stresses ◽  
Flow Direction ◽  
Three Dimensional ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Three Dimensional Model

In this work a three-dimensional model of a solid oxide fuel cell (SOFC) has been developed and is used to predict the temperature, concentration distribution and velocity profile across the cell. This model employs Users’ Subroutines in a commercial computational fluid dynamics (CFD) code to simulate the electrochemical reactions. The results show both fuel concentration and current density decreasing along the flow direction. The temperature differences are significant with the hottest point located in middle of the active area. Increasing the operating temperature is shown to reduce the effect of polarization that hampers the cell performance, although other issues such as thermal stresses and reduced material choices are more significant.

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