Turbulent Flow in Axially Rotating Pipes

1980 ◽  
Vol 102 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Mitsukiyo Murakami ◽  
Kouji Kikuyama
Keyword(s):  
Velocity Profile ◽  
Turbulent Flow ◽  
Flow Pattern ◽  
Axial Velocity ◽  
Hydraulic Loss ◽  
Pressure Distributions ◽  
Axial Velocity Profile ◽  
Fully Developed Turbulent Flow ◽  
Smooth Pipe ◽  
Pipe Rotation

Experimental results concerning the flow pattern and hydraulic resistance in a rotating pipe are described. A fully developed turbulent flow was introduced into a long smooth pipe rotating about its axis, and changes of the flow pattern, together with hydraulic loss within the pipe, were examined by measuring the velocity and pressure distributions across sections at various distance from the pipe entrance. Increase of pipe rotation continuously reduces the hydraulic loss and gradually changes the axial velocity profile from a turbulent type to a laminar one. Governing factors for these changes are discussed.

Merging flows in an arterial confluence: the vertebro-basilar junction

1995 ◽  
Vol 304 ◽  
pp. 119-141 ◽  
Author(s):  
J. Ravensbergen ◽  
J. K. B. Krijger ◽  
B. Hillen ◽  
H. W. Hoogstraten
Keyword(s):  
Velocity Profile ◽  
Flow Pattern ◽  
Basilar Artery ◽  
Axial Velocity ◽  
Average Length ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Axial Velocity Profile ◽  
Flow Phenomena ◽  
Junction Geometry

The basilar artery is one of the three vessels providing the blood supply to the human brain. It arises from the confluence of the two vertebral arteries. In fact, it is the only artery of this size in the human body arising from a confluence instead of a bifurcation. Earlier work, concerning flow computations in simplified models of the basilar artery, has demonstrated that a junction causes distinctive flow phenomena. This paper presents three-dimensional finite-element computations of steady viscous flow in a rigid symmetrical junction geometry representing the anatomical situation in a more realistic way. The geometry consists of two round tubes merging into a single round outlet tube. The Reynolds number for the basilar artery ranges from 200 to 600, and both symmetrical and asymmetrical inflow from the two inlet tubes has been considered.Just downstream of the confluence a ‘double hump’ axial velocity profile is found. In the transition zone the flow pattern appears to have a complicated structure. In the symmetrical case the axial velocity profile shows a sharp central ridge, whereas in the asymmetrical case the highest ‘hump’ crosses the centreline of the tube. The flow has a highly three-dimensional character with secondary velocities easily exceeding 25% of the mean axial flow velocity. The secondary flow pattern consists of four vortices. Under all simulated flow conditions, the inlet length turns out to be much larger than the average length of the human basilar artery.To validate the computational model, a comparison is made between numerical and experimental results for a junction geometry consisting of tubes with a rectangular cross-section. The experiments have been performed in a Perspex model with laser Doppler velocimetry and dye injection techniques. Good agreement between experimental and computational results is found. Moreover, all essential flow phenomena turn out to be quite similar to those obtained for the circular tube geometry.

Computational analysis of turbulent flow through an eccentric annulus under different temperature conditions

2018 ◽  
Vol 28 (9) ◽  
pp. 2189-2207 ◽  
Author(s):  
Erman Ulker ◽  
Sıla Ovgu Korkut ◽  
Mehmet Sorgun
Keyword(s):  
Turbulent Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Content Type ◽  
Non Linear ◽  
Fully Developed Turbulent Flow ◽  
Effects Of Temperature ◽  
Eccentric Annuli ◽  
Pipe Rotation

Purpose The purpose of this paper is to solve Navier–Stokes equations including the effects of temperature and inner pipe rotation for fully developed turbulent flow in eccentric annuli by using finite difference scheme with fixing non-linear terms. Design/methodology/approach A mathematical model is proposed for fully developed turbulent flow including the effects of temperature and inner pipe rotation in eccentric annuli. Obtained equation is solved numerically via central difference approximation. In this process, the non-linear term is frozen. In so doing, the non-linear equation can be considered as a linear one. Findings The convergence analysis is studied before using the method to the proposed momentum equation. It reflects that the method approaches to the exact solution of the equation. The numerical solution of the mathematical model shows that pressure gradient can be predicted with a good accuracy when it is compared with experimental data collected from experiments conducted at Izmir Katip Celebi University Flow Loop. Originality/value The originality of this work is that Navier–Stokes equations including temperature and inner pipe rotation effects for fully developed turbulent flow in eccentric annuli are solved numerically by a finite difference method with frozen non-linear terms.

The Elimination of Wall Effects in Axial-Flow Compressor Stages

1953 ◽  
Vol 57 (508) ◽  
pp. 241-243
Author(s):  
J. M. Stephenson
Keyword(s):  
Velocity Profile ◽  
Axial Velocity ◽  
Radial Profile ◽  
Axial Flow ◽  
Gas Velocity ◽  
Wall Effects ◽  
Axial Velocity Component ◽  
Axial Velocity Profile ◽  
Flow Compressor ◽  
Work Done

Compressor stages are usually designed on the assumption that the gas velocity is nowhere affected by the friction at the walls. The only way in which viscosity is taken into account is in the assumed efficiency, and in a guessed “work-done factor,” which ensures that by aiming high the required work is actually attained.It is known that the radial profile of the axial velocity component becomes more and more peaked through successive stages of a compressor, so that the assumptions just quoted become very inaccurate. It is possible that the efficiency of a stage could be raised considerably if the axial velocity profile were controlled; moreover up to 20 per cent. more work could be done if a “ work-done factor ” did not have to be applied.

A Theoretical Analysis of the Influence of Rotation on Flow in a Tube Rotating about a Parallel Axis with Uniform Angular Velocity

1965 ◽  
Vol 69 (651) ◽  
pp. 201-202 ◽  
Author(s):  
W. D. Morris
Keyword(s):  
Angular Velocity ◽  
Velocity Profile ◽  
Axial Velocity ◽  
Cylindrical Tube ◽  
Fluid Flows ◽  
Leading Edge ◽  
Pressure Fields ◽  
Axial Velocity Profile ◽  
Parallel Axis ◽  
Arbitrary Axis

When fluid flows in a tube which rotates about an arbitrary axis, the presence of centripetal and Coriolis acceleration components modify the velocity and pressure fields which exist in the absence of rotation. Barua considered the case of an incompressible fluid flowing in laminar motion through a cylindrical tube which was rotating about an axis perpendicular to itself with uniform angular velocity. For distances well away from the tube entrance Barua illustrated that secondary flow in the r-θ plane occurred and that the axial velocity profile was distorted towards the leading edge of the tube. Since the pressure gradient along the tube is proportional to the gradient of the axial velocity profile at the tube wall the rotation thus has a consequential influence on the resistance to flow offered by the tube.

Gas Dispersion in a Model Pulmonary Bifurcation During Oscillatory Flow

1997 ◽  
Vol 119 (3) ◽  
pp. 309-316 ◽  
Author(s):  
M. Nishida ◽  
Y. Inaba ◽  
K. Tanishita
Keyword(s):  
Velocity Profile ◽  
Axial Velocity ◽  
Oscillatory Flow ◽  
Gas Transport ◽  
Main Bronchus ◽  
High Frequency Oscillation ◽  
Laser Doppler Velocimeter ◽  
Straight Tube ◽  
Gas Dispersion ◽  
Axial Velocity Profile

In order to clarify the gas transport process in high-frequency oscillation, we measured the axial velocity profile and the axial effective diffusivity in a single asymmetric bifurcating tube, based on the Horsfield airway model, with sinusoidally oscillatory flow. The axial velocity profiles were measured using a laser-Doppler velocimeter, and the effective diffusivities were evaluated using a simple bolus injection method. The axial velocity profile was found to be nonuniform, promoting axial gas dispersion by the spread of the concentration profile and lateral mixing. The geometric asymmetry of the bifurcation was responsible for the difference in gas transport between the main bronchi. The axial gas transport in the left main bronchus was 2.3 times as large as that of the straight tube, whereas the gas transport in the right main bronchus was slightly larger than that of the straight tube. Thus localized variation in gas transport characterized the heterogeneous respiratory function of the lung.

Compressor Design

1953 ◽  
Vol 57 (511) ◽  
pp. 463-463
Author(s):  
R. G. Taylor
Keyword(s):  
Velocity Profile ◽  
Axial Velocity ◽  
Axial Flow ◽  
Technical Note ◽  
Basic Design ◽  
Wall Effects ◽  
Axial Flow Compressor ◽  
Axial Velocity Profile ◽  
Compressor Design ◽  
Flow Compressor

In Mr. J. M. Stephenson's Technical Note, “ The Elimination of Wall Effects in Axial-Flow Compressor Stages,” in the April 1953 issue of the Journal, the author suggests that the blade rows of an axial flow compressor are so closely spaced as to ensure that the axial velocity profile is unchanged across the rows. Whether this statement is correct or not such an assumption regarding the axial velocity profile is a basic design condition and when made it will not leave any flexibility in the choice of the function f(r).

scholarly journals A Study of Oscillatory Flow in Curved Pipes : 2nd Report, Axial Velocity Profile

1985 ◽  
Vol 28 (245) ◽  
pp. 2644-2651
Author(s):  
Kouzou SUDOU ◽  
Masaru SUMIDA ◽  
Toshihiro TAKAMI ◽  
Ryuichiro YAMANE
Keyword(s):  
Velocity Profile ◽  
Axial Velocity ◽  
Oscillatory Flow ◽  
Curved Pipes ◽  
Axial Velocity Profile

Hemodynamics for Asymmetric Inlet Axial Velocity Profile in Carotid Bifurcation Model

2008 ◽  
Vol 20 (5) ◽  
pp. 656-661 ◽  
Author(s):  
Zu-rong Ding ◽  
Bin Liu ◽  
Shuo Yang ◽  
Yan Xia
Keyword(s):  
Velocity Profile ◽  
Axial Velocity ◽  
Carotid Bifurcation ◽  
Axial Velocity Profile
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