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Turbulence measurements in a round jet beneath a free surface

Published online by Cambridge University Press:  26 April 2006

D. G. Anthony  and
W. W. Willmarth
D. G. Anthony
Affiliation:
David Taylor Research Center, Bethesda, MD 20084-5000. USA
W. W. Willmarth
Affiliation:
Department of Aerospace Engineering, The University of Michigan. Ann Arbor. MI 48109-2140, USA
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Abstract

The results of an experimental investigation of a turbulent jet flow issuing from a circular nozzle beneath and parallel to a free surface are presented. Measurements of the mean velocity vector and all components of the Reynolds stress tensor were made using a three-component, underwater laser-Doppler velocimeter (LDV). Visualizations of the flow field using both fluorescent dye and free-surface shadowgraphs were made in support of the measurements. The jet is observed to form a shallow surface current, the lateral extent of which is significantly greater than that of the primary jet flow that produces it. Flow visualization reveals the surface current to consist largely of fluid structures ejected from the jet. These structures remain coherent within the current, apparently as a consequence of reduced turbulent mixing just beneath the surface. LDV measurements of the turbulence within the surface current reveal that near the jet centreline, where the interaction between the jet and the free surface is most intense, the velocity fluctuations normal to the free surface are diminished in approaching the surface, while the fluctuations parallel to the surface are enhanced. Away from the jet centreline, toward the edges of the surface current, the vertical and cross-stream fluctuations become approximately equal in magnitude, whereas the streamwise fluctuations become diminished. This is attributed, in part, to orbital motions beneath surface waves generated by the interaction of large-scale jet structures with the surface. When oleyl alcohol, an insoluble surface-active agent, was added to the free surface, the surface current was not observed. Comparisons between a jet issuing beneath both clean and surfactant-contaminated free surfaces, and a jet issuing beneath a solid wall are made to identify the role of streamwise vorticity and of secondary vorticity generated at boundaries on the development of these flows.

Information

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 243 , October 1992 , pp. 699 - 720
Copyright
© 1992 Cambridge University Press

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References

Abramovich, G. N. 1963 The Theory of Turbulent Jets. MIT.
Anthony, D. G. 1990 The influence of a free surface on the development of turbulence in a submerged jet. Ph.D. thesis, University of Michigan.
Anthony, D. G., Hirsa, A. & Willmarth, W. W. 1991 On the interaction of a submerged turbulent jet with a clean or contaminated free surface.. Phys. Fluids A 3, 245–247.Google Scholar
Bernal, L. P., Hirsa, A., Kwon, J. T. & Willmarth, W. W. 1989 On the interaction of vortex rings and pairs with a free surface for varying amounts of surface active agent.. Phys. Fluids A 1, 2001–2004.Google Scholar
Bernal, L. P. & Madnia, K. 1988 Interaction of a turbulent round jet with the free surface. Proc. 17th Symp. Naval Hydrodynamics. Washington: National Academy Press.
Davis, M. R. & Winarto, H. 1980 Jet diffusion from a circular nozzle above a solid wall. J. Fluid Mech. 101, 201–221.Google Scholar
Gaines, G. L. 1966 Insoluble Monolayers at Liquid-Gas Interfaces. Interscience.
Hirsa, A. 1990 An experimental investigation of vortex pair interaction with a clean or contaminated free surface. Ph.D. thesis, University of Michigan.
Johnston, V. G. & Walker, D. T. 1991 Experimentally observed features of the turbulent nearwake of a model ship. Tech. Rept. 92–1, Univ. Mich. Program in Ship Hydrodynamics, ONR Contract N000184–86-K-0684, Jan. 1992.
Komori, S., Ueda, H., Ogino, F. & Mizushima, T. 1982 Turbulence structure and transport mechanism at the free surface in an open channel flow. Intl J. Heat Mass Transfer 25, 513–521.Google Scholar
Launder, B. E. & Rodi, W. 1981 The turbulent wall jet. Prog. Aerosp. Sci. 19, 81–128.Google Scholar
Launder, B. E. & Rodi, W. 1983 The turbulent wall jet — measurements and modeling. Ann. Rev. Fluid Mech., 15, 429–459.Google Scholar
Liepmann, D. 1990 The near-field dynamics and entrainment field of submerged and near-surface jets. Ph.D. thesis, University of California, San Diego.
Lyden, J D., Hammond, R. R. Lyzenga, D. R. & Shuchman, R. A. 1988 synthetic aperture radar imaging of surface ship wakes. J. Geophysical Res. 93 (C10), 12293–12303.
Mclaughlin, D. K. & Tiederman, W. G. 1973 Biasing correction for individual realization of laser anemometer measurements in turbulent flow. Phys. Fluids 16, 2082–2088.Google Scholar
Munk, W. H., Scully-Power, P. & Zachariesen, F. 1987 Ship wakes from space: the Bakerian lecture, 1986.. Proc. R. Soc. Lond. A 412, 231–254.Google Scholar
Newman, B. G., Patel, R. P. Savage, S. B. & Tjio, H. K. 1972 Three-dimensional wall jet originating from a circular orifice. Aeronaut. Q. 23, 188–200.Google Scholar
Rajaratnam, N. 1976 Turbulent Jets. Elsevier.
Rajaratnam, N. & Humphries, L. A. 1984 Turbulent non-buoyant surfaces jets. J. Hydraul. Res. 22, 103–115.Google Scholar
Rajaratnam, N. & Humphries, L. A. 1984 Turbulent non-buoyant surface jets. J. Hydraul. Res. 22, 103–115.Google Scholar
Rajaratnam, N. & Subramanyan, S. 1985 Plane turbulent buoyant surface jets. J. Hydraul. Res. 23, 131–146.Google Scholar
Rashidi, M. & Banerjee, S. 1988 Turbulence structure in free-surface channel flows. Phys. Fluids 31, 2491–2503.Google Scholar
Swean, T. F., Ramberg, S. E., Plesniak, M. W. & Stewart, M. B. 1989 Turbulent surface jet in channel of limited depth. J. Hydraul. Engng. 115, 1587–1606.Google Scholar
Willmarth, W. W. 1987 Design of three component fiber optic laser Doppler anemometer for wake measurements in a towing tank. Proc. Intl Towing Tank Conf., 18–24 Oct. 1987, Kobe, Japan, Vol. 2, pp. 338–391.
Wygnanski, I. & Fiedler, H. 1969 Some measurements in the self-preserving jet. J. Fluid Mech. 38, 577–612.Google Scholar