Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-28T07:53:39.604Z Has data issue: false hasContentIssue false

Observations and LDA measurements of confined turbulent vortex flow

Published online by Cambridge University Press:  19 April 2006

M. P. Escudier
Affiliation:
Brown Boveri Research Centre, CH-5405 Baden-Dättwil, Switzerland
J. Bornstein
Affiliation:
Brown Boveri Research Centre, CH-5405 Baden-Dättwil, Switzerland
N. Zehnder
Affiliation:
Brown Boveri Research Centre, CH-5405 Baden-Dättwil, Switzerland

Abstract

A series of LDA measurements and visual observations of confined turbulent vortex flow are described. The experiments were performed with water as the fluid medium in a vortex tube of length-to-diameter ratio L/D = 3.8 for a range of exit diameters De between De/D = 1 and 0.18. The experiments reveal a remarkable change in the vortex structure as De is reduced: from a thick core with an axial-velocity defect in the centre, and even reversed flow, to a thin annular jet-like core with a peak axial velocity more than an order of magnitude greater than the average value and again a central velocity deficit. The corresponding swirl profiles are not remarkable and are well-represented under all conditions by the solution of Burgers (1948), albeit with a velocity maximum which is strongly dependent upon De.

Type
Research Article
Copyright
© 1980 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.)

Footnotes

Laser-Doppler anemometer.

References

Baker, G. R., Barker, S. J., Bofah, K. K. & Saffman, P. G. 1974 Laser anemometer measurements of trailing vortices in water. J. Fluid Mech. 65, 325.Google Scholar
Binnie, A. M. & Teare, J. D. 1956 Experiments on the flow of swirling water through a pressure nozzle and an open trumpet. Proc. Roy. Soc. A 235, 78.Google Scholar
Bödewadt, U. T. 1940 Die Drehströmung über festem Grunde. Z. angew. Math. Mech. 20, 241.Google Scholar
Burgers, J. M. 1948 A mathematical model illustrating the theory of turbulence. Adv. Appl. Mech. 1, 198.Google Scholar
Cassidy, J. J. & Falvey, H. T. 1970 Observations of unsteady flow arising after vortex breakdown. J. Fluid Mech. 41, 727.Google Scholar
Chanaud, R. C. 1965 Observations of oscillatory motion in certain swirling flows. J. Fluid Mech. 21, 111.Google Scholar
Donaldson, C. du P. & Snedeker, R. S. 1962 Experimental investigation of the structure of vortices in simple cylindrical vortex chambers. Aero. Res. Ass. of Princeton, Inc. Rep. no. 47.Google Scholar
Donaldson, C. du P. & Sullivan, R. D. 1960 Behaviour of solutions of the Navier-Stokes equations for a complete class of three-dimensional viscous vortices. Proc. 1960 Heat Transfer and Fluid Mech. Inst., p. 16. Stanford University Press.
Escudier, M. P. 1979 Estimation of pressure loss in ring-type exit chambers. Trans. A.S.M.E. I, J. Fluids Engng 101, 511.Google Scholar
Escudier, M. P. & Merkli, P. 1979 Observations of the oscillatory behaviour of a confined ring vortex. A.I.A.A. J. 17, 253.Google Scholar
Faler, J. H. 1976 Some experiments in swirling flows: detailed velocity measurements of a vortex breakdown using a laser Doppler anemometer. N.A.S.A. Contractor Rep. no. 135115.Google Scholar
Faler, J. H. & Leibovich, S. 1977 Disrupted states of vortex flow and vortex breakdown. Phys. Fluids 20, 1385.Google Scholar
Faler, J. H. & Leibovich, S. 1978 An experimental map of the internal structure of a vortex breakdown. J. Fluid Mech. 86, 313.Google Scholar
Holman, J. P. & Moore, G. D. 1961 An experimental study of vortex chamber flow. Trans. A.S.M.E. D, J. Basic Engng 83, 632.Google Scholar
Iten, P. D. & Dändliker, R. 1972 A sampling wide-band demodulator useful for laser Doppler velocimeters. Proc. I.E.E.E. 60, 1470.Google Scholar
Keller, J. J. & Escudier, M. P. 1980 Theory and observations of waves on hollow-core vortices. J. Fluid Mech. (to appear).Google Scholar
Keynes, J. J. 1960 An experimental study of gas dynamics in high velocity vortex flow. Proc. 1960 Heat Transfer and Fluid Mech. Inst., p. 31. Stanford University Press.
Lewellen, W. S. 1971 A review of confined vortex flows. N.A.S.A. Contractor Rep. no. 1772.Google Scholar
Merkli, P. & Escudier, M. P. 1979 Observations of flow in a ring inlet chamber. Trans. A.S.M.E. I, J. Fluids Engng 101, 135.Google Scholar
Nuttall, J. B. 1953 Axial flow in a vortex. Nature 172, 582.Google Scholar
Orloff, K. L. 1974 Trailing vortex wind-tunnel diagnostics with a laser velocimeter. A.I.A.A. J. Aircraft 11, 477.Google Scholar
Orloff, K. L. & Bossel, H. H. 1973 Laser Doppler velocity measurements of swirling flows with upstream influence. N.A.S.A. Contractor Rep. no. 2284.Google Scholar
Sullivan, R. D. 1959 A two-cell vortex solution of the Navier-Stokes equations. J. Aero. Space Sci. 26, 767.Google Scholar