scholarly journals Three-dimensional steady and oscillatory flow in a double bifurcation airway model

2018 ◽  
Vol 3 (10) ◽  
Author(s):  
Sahar Jalal ◽  
Tristan Van de Moortele ◽  
Andras Nemes ◽  
Omid Amili ◽  
Filippo Coletti
Keyword(s):  
Oscillatory Flow ◽  
Three Dimensional ◽  
Airway Model

Numerical Simulation Study on the Asymmetric Structures of Oscillatory Flow Field in a Baffled Tube Reactor

2004 ◽  
Author(s):  
Yong-Wen Wu ◽  
Jia Wu
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flows ◽  
Oscillatory Flow ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Structured Grid ◽  
Tube Reactor ◽  
Oscillating Boundary ◽  
The Asymmetry ◽  
Laminar And Turbulent Flows

The oscillatory flow in a baffled tube reactor provides a significant enhancement of radial transfer of momentum, heat and mass and a good control of axial back mixing at a wide range of net flow rate. But little has been known about reliable details of the three-dimensional structure of flow field in this kind of flow because most published studies in the area were based on the two-dimensional simulation techniques. This paper implemented a three-dimensional numerical simulation study on the asymmetry of flow pattern in the baffled tube reactor which was observed experimentally. A systematic study by numerical simulation was carried out which covered a range of oscillatory Reynolds number (Reo) from 100 to 5,000 and employed models respectively for laminar and turbulent flows. It was found in the simulation that under symmetric boundary conditions the transition from axially symmetric flow to asymmetric one depended on the numerical technique employed in simulation. With a structured grid frame the transition occurred at Reo much greater than that with an unstructured grid frame, for both laminar and turbulent flows. It is not rational that the onset of the transition changes with the accuracy of numerical technique. Based on the simulation results, it was postulated that the asymmetry appeared in simulations with symmetric boundary conditions might result from the accumulation of calculation errors but the asymmetry observed in experiments might result from the slight asymmetry of geometry which exists inevitably in any experiment apparatus. To explore the influence of the slight asymmetry of geometry, the effect of the eccentricity of baffles and the declination of oscillating boundary were studied by use of the finite volume method with a structured grid and adaptive time steps. The simulation result showed that both the eccentricity of baffles and the declination of oscillating boundary have obvious influence on the asymmetry of flow patterns for laminar and turbulent flow. More details were discussed in the paper.

The development of asymmetry and period doubling for oscillatory flow in baffled channels

1996 ◽  
Vol 328 ◽  
pp. 19-48 ◽  
Author(s):  
E. P. L. Roberts ◽  
M. R. Mackley
Keyword(s):  
Reynolds Number ◽  
Oscillatory Flow ◽  
Three Dimensional ◽  
Period Doubling ◽  
Progressive Increase ◽  
Newtonian Flow ◽  
Chaotic Flow ◽  
Spatially Periodic ◽  
Dimensional Simulation ◽  
Time Periodic

We report experimental and numerical observations on the way initially symmetric and time-periodic fluid oscillations in baffled channels develop in complexity. Experiments are carried out in a spatially periodic baffled channel with a sinusoidal oscillatory flow. At modest Reynolds number the observed vortex structure is symmetric and time periodic. At higher values the flow progressively becomes three-dimensional, asymmetric and aperiodic. A two-dimensional simulation of incompressible Newtonian flow is able to follow the flow pattern at modest oscillatory Reynolds number. At higher values we report the development of both asymmetry and a period-doubling cascade leading to a chaotic flow regime. A bifurcation diagram is constructed that can describe the progressive increase in complexity of the flow.

Supersonic mixing enhanced by cavity-induced three-dimensional oscillatory flow

2014 ◽  
Vol 55 (4) ◽  
Author(s):  
Taro Handa ◽  
Aoi Nakano ◽  
Kazuya Tanigawa ◽  
Jun Fujita
Keyword(s):  
Oscillatory Flow ◽  
Three Dimensional ◽  
Supersonic Mixing

scholarly journals Printed three-dimensional airway model assists planning of single-lung ventilation in a small child

2015 ◽  
Vol 115 (4) ◽  
pp. 616-620 ◽  
Author(s):  
C.A. Wilson ◽  
O.J. Arthurs ◽  
A.E. Black ◽  
S. Schievano ◽  
C. Hunt ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Lung Ventilation ◽  
Small Child ◽  
Single Lung Ventilation ◽  
Airway Model

Swirling Flow Over an Oscillatory Stretchable Disk

2014 ◽  
Vol 30 (4) ◽  
pp. 339-347 ◽  
Author(s):  
S. Munawar ◽  
A. Ali ◽  
N. Saleem ◽  
A. Naqeeb
Keyword(s):  
Oscillatory Flow ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Finite Domain ◽  
Governing Equations ◽  
Infinite Domain ◽  
Similarity Transformations ◽  
Sinusoidal Oscillations ◽  
Dimensional Boundary ◽  
Layer Flow

AbstractIn this work a numerical investigation has been conducted to study the unsteady oscillatory flow of a viscous fluid induced by a swirling disk. The disk stretches radially with the time-based sinusoidal oscillations. The governing equations for the three-dimensional boundary layer-flow are normalized using a suitable set of similarity transformations. The normalized partial differential equations are then solved numerically using a finite difference scheme by altering the semi-infinite domain to a finite domain. The effects of various imperative parameters on the oscillatory flow are discussed with graphs and tables.

Thermocapillary Convection of Low Prandtl Number Fluid in a Shallow Cylindrical Pool

2006 ◽  
Author(s):  
Fang Ling ◽  
You-Rong Li ◽  
Peng Lan ◽  
Shuang-Ying Wu ◽  
Qing-Hua Chen
Keyword(s):  
Prandtl Number ◽  
Marangoni Number ◽  
Oscillatory Flow ◽  
Thermocapillary Convection ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Critical Conditions ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Oscillation Frequencies

In order to understand the characteristics of thermocapillary convection, we conducted a series of unsteady three-dimensional numerical simulations of thermocapillary convection of low Prandtl number fluid in a shallow cylindrical pool with an azimuthal nonuniform temperature, an adiabatic solid bottom and free surface. The simulation results indicate that thermocapillary convection is steady three-dimensional flow at the small Marangoni number. But when Marangoni number exceeds some critical value, the flow will undergo a transition to oscillatory three-dimensional flow. The critical conditions for the onset of oscillatory flow are determined. Details of the flow and temperature fields are discussed, and oscillation frequencies are also exhibited.

Oscillatory flow in image-based bronchial airway model

2006 ◽  
Vol 39 ◽  
pp. S601-S602
Author(s):  
G. Tanaka ◽  
G. Inagaki ◽  
M. Hishida ◽  
H. Haneishi ◽  
X. Hu
Keyword(s):  
Oscillatory Flow ◽  
Airway Model
Sign in / Sign up

Export Citation Format

Share Document