Hostname: page-component-848d4c4894-2xdlg Total loading time: 0 Render date: 2024-06-16T04:49:27.684Z Has data issue: false hasContentIssue false
  • English
  • Français

An experimental investigation of pulsating turbulent water flow in a tube

Published online by Cambridge University Press:  29 March 2006

J. H. Gerrard
J. H. Gerrard
Affiliation:
Department of the Mechanics of Fluids, University of Manchester
Get access Rights & Permissions [Opens in a new window]

Abstract

Experiments were made on a pulsating water flow at a mean flow Reynolds number of 3770 in a cylindrical tube of diameter 3·81 cm. Pulsations were produced by a piston oscillating in simple harmonic motion with a period of 12 s. Turbulence was made visible by means of a sheet of dye produced by electrolysis from a fine wire stretched across a diameter. The sheet of dye is contorted by the turbulent eddies, and ciné-photography was used to find the velocity of convection which was shown to be the flow speed except in certain circumstances which are discussed. By subtracting the mean flow velocity profile the profile of the component of the motion oscillating at the imposed frequency was determined.

The Reynolds number of these experiments lies in the turbulent transition range, so that large effects of laminarization are observed. In the turbulent phase, the velocity profile was found to possess a central plateau as does the laminar oscillating profile. The level and radial extent of this were little different from the laminar ones. Near to the wall, the turbulent oscillating profile is well represented by the mean velocity power law relationship, u/U ∝ (y/a)1/n. In the laminarized phase, the turbulent intensity is considerably reduced at this Reynolds number. The velocity profile for the whole flow (mean plus oscillating) relaxes towards the laminar profile. Laminarization contributes appreciably to the oscillating component.

Extrapolation of the results to higher Reynolds numbers and different frequencies of oscillation is suggested.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 46 , Issue 1 , 15 March 1971 , pp. 43 - 64
Copyright
© 1971 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baker, D. J. 1966 A technique for the precise measurement of small fluid velocities J. Fluid Mech. 26, 573.Google Scholar
Brinkworth, B. J. & Smith, P. C. 1969 Velocity distribution in the core of a turbulent pipe flow Chem. Eng. Sci. 24, 787.Google Scholar
Combs, G. D. 1964 A stability study for pulsating flow in rigid tubes. Ph.D. Thesis, University of Arkansas.
Davis, W. & Fox, R. W. 1967 An evaluation of the hydrogen bubble technique for the quantitative determination of fluid velocities within clear tubes J. Basic Engng 89, 771.Google Scholar
Laufer, J. 1954 The structure of turbulence in fully developed pipe flow. NACA Rep. no. 1174.Google Scholar
Linford, R. G. & Ryan, N. W. 1965 Pulsatile flow in rigid tubes J. Appl. Physiol. 20, 1078.Google Scholar
Patel, V. C. & Head, M. R. 1969 Some observations on skin friction and velocity profiles in fully developed pipe and channel flows J. Fluid Mech. 38, 181.Google Scholar
Sandborn, V. A. 1955 Experimental evaluation of the momentum terms in turbulent pipe flow. NACA Tech. Note no. 3266.Google Scholar
Schlichting, H. 1955 Boundary Layer Theory (1st English edn). Oxford: Pergamon.
Senecal, V. E. & Rothfus, R. R. 1953 Transition flow in smooth tubes Chem. Engng Prog. 49, 533.Google Scholar
Sexl, T. 1930 Über den von E. G. Richardson entdeckten ‘Annulareffekt’. Z. Phys. 61 349.Google Scholar
Szymanski, F. 1930 Quelques solutions exactes des equations de l'hydrodynamique de fluide visqueux dans le cas d'un tube cylindrique Proc. 3rd Int. Congr. Appl. Mech. 1, 249.Google Scholar
Uchida, S. 1956 The pulsating viscous flow superposed on the steady motion of incompressible fluid in a circular pipe Z.A.M.P. 7, 403.Google Scholar
Womersley, J. R. 1955 Oscillatory motion of a viscous fluid in a thin walled elastic tube Phil. Mag. 46, 199.Google Scholar