Flow Regulation Characteristics of Thin-Walled Compliant Tubes: Part I—Theoretical Analysis

1990 ◽  
Vol 112 (3) ◽  
pp. 319-329
Author(s):  
Ifiyenia Kececioglu
Keyword(s):  
Reynolds Number ◽  
Wave Speed ◽  
Active Element ◽  
Flow Regulation ◽  
Collapsible Tube ◽  
Speed Flow ◽  
Thin Walled ◽  
Flow Regulator ◽  
High Reynolds ◽  
Set Up

The objective of this investigation is the study of the flow limitation behavior of thin-walled compliant tubes for the design of a flow regulator employing a collapsible tube as its active element. In this paper, the theoretical basis is set up for the high-Reynolds-number wave-speed flow regulation and the low-Reynolds-number frictional flow regulation behaviors of thin-walled compliant tubes. In Part II of this paper [1], experimental results and design criteria are provided in support of the analytically derived characteristic flow regulation curve for the wave-speed flow regulator.

Flow Regulation Characteristics of Thin-Walled Compliant Tubes: Part II—Experimental Verification and Design of the Wave-Speed Flow Regulator

1990 ◽  
Vol 112 (3) ◽  
pp. 330-337
Author(s):  
Ifiyenia Kececioglu
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Wave Speed ◽  
Tube Flow ◽  
Flow Limitation ◽  
Reynolds Number Flow ◽  
Speed Flow ◽  
Number Flow ◽  
Flow Regulator ◽  
High Reynolds

The theoretical foundation of the two different mechanisms of compliant-tube flow limitation when the flow is either friction dominated (frictional flow limitation for low-Reynolds-number flow) or inertia dominated (wave-speed flow limitation for high-Reynolds-number flow) was formulated in Part I [1] of this paper. In this part of the paper, the high-Reynolds-number wave-speed flow limitation behavior of compliant tubes is verified experimentally and applied to the design of a flow regulator employing a collapsible tube as its active element. Criteria for the design of an inertia-dominated compliant-tube flow regulator are established and checked against findings of experiments.

Transient Simulation of Flow Past Smooth Circular Cylinder at very High Reynolds Number Using OpenFOAM

2014 ◽  
Vol 592-594 ◽  
pp. 1972-1977 ◽  
Author(s):  
Sangamesh M. Hosur ◽  
D.K. Ramesha ◽  
Suman Basu
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Open Source ◽  
High Reynolds Number ◽  
Numerical Data ◽  
Flow Past ◽  
Computational Fluid Dynamics Cfd ◽  
High Reynolds ◽  
Set Up ◽  
Free Open Source

Flow past a smooth circular cylinder at high Reynolds number (Re=3.6 x 106) which covers the upper-transition regime has been investigated numerically by using Open source Field Operation and Manipulation (OpenFOAM) package. OpenFOAM is a free, open source Computational Fluid Dynamics (CFD) software package. The numerical model has been set up as two dimensional (2D), transient, incompressible and turbulent flow. A standard high Reynolds number k-ε turbulence model is included to evaluate the turbulence. The objective of the present work is to set up the case using pimpleFoam solver which is an Unsteady Reynolds Averaged Simulations (URANS) model and to evaluate the model for its conformance with available literature and experiments. The results obtained are compared with experimental and numerical data.

Absolute and Convective Instabilities of a Collapsible Tube

2002 ◽  
Author(s):  
Hamadiche Mahmoud
Keyword(s):  
Reynolds Number ◽  
Unstable Mode ◽  
Standing Waves ◽  
Cusp Point ◽  
Collapsible Tube ◽  
Convective Instabilities ◽  
Cusp Points ◽  
The Absolute ◽  
High Reynolds ◽  
Good Agreement

In this paper we extend a numerical method, developed previously by the author, to compute the eigen modes of collapsible viscoelastic duct convening a fowing fuid. A new technique is developed in order to eliminate the need for recurrence formula used in the old method. This gives a more powerful and tractable method to find the eigen modes of the system. The new method has allowed the identification of a new unstable modes in a collapsible tube. It is found that there is a set of standing non axisymmetric waves representing an absolute instabilities and a set of unstable upstream and downstream propagated waves representing a convective instabilities. Two standing waves have equal frequency in their cusp points. The frequency of the other standing waves, in their cusp points, are a multiple of the frequency of the first wave and that in good agreement with experimental finding available in the literature. It is found that the first absolute unstable mode becomes convective at high Reynolds number while the other standing wave remain absolutely unstable modes for Re higher than 100. The frequency ratio of the absolute unstable modes in their cusp point are preserved for all Reynolds number and that with an good agreement with the experience. The absolute unstable mode which becomes convective at high Reynolds number keeps a monochromatic wave with a frequency equal to the frequency of the second absolute unstable mode, in its cusp point, and that for all Reynolds number higher than the limit of absolute instability of the first mode in surprising agreement with the experimental results. It is founded that the viscosity of the solid stabilizes the standing wavesat different degree. The boundary separating the absolute instabilities zone from the convective instabilities zone are found.

Linear stability of Poiseuille flow in a circular pipe

1980 ◽  
Vol 98 (2) ◽  
pp. 273-284 ◽  
Author(s):  
Harold Salwen ◽  
Fredrick W. Cotton ◽  
Chester E. Grosch
Keyword(s):  
Reynolds Number ◽  
Linear Stability ◽  
Poiseuille Flow ◽  
Wave Speed ◽  
Complete Agreement ◽  
Matrix Elements ◽  
Wave Speeds ◽  
Complex Wave ◽  
The Matrix ◽  
High Reynolds

Correction of an error in the matrix elements used by Salwen & Grosch (1972) has brought the results of the matrix-eigenvalue calculation of the linear stability of Hagen–Poiseuille flow into complete agreement with the numerical integration results of Lessen, Sadler & Liu (1968) for azimuthal index n = 1. The n = 0 results were unaffected by the error and the effect of the error for n > 1 is smaller than for n = 1. The new calculations confirm the conclusion that the flow is stable to infinitesimal disturbances.Further calculations have led to the discovery of a degeneracy at Reynolds number R = 61·452 ± 0·003 and wavenumber α = 0·9874 ± 0·0001, where the second and third eigenmodes have equal complex wave speeds. The variation of wave speed for these two modes has been studied in the vicinity of the degeneracy and shows similarities to the behaviour near the degeneracies found by Cotton and Salwen (see Cotton 1977) for rotating Hagen-Poiseuille flow. Finally, new results are given for n = 10 and 30; the n = 1 results are extended to R = 106; and new results are presented for the variation of the wave speed with αR at high Reynolds number. The high-R results confirm both Burridge & Drazin's (1969) slow-mode approximation and more recent fast-mode results of Burridge.

Modeling and Simulation of High Reynolds' Number Flows During Reaction Injection Mold Filling

1994 ◽  
Vol 9 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Rahima K. Mohammed ◽  
Tim A. Osswald ◽  
Timothy J. Spiegelhoff ◽  
Esther M. Sun
Keyword(s):  
Reynolds Number ◽  
Modeling And Simulation ◽  
High Reynolds Number ◽  
Mold Filling ◽  
Injection Mold ◽  
High Reynolds ◽  
Reynolds Number Flows
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