Hostname: page-component-7b7567c8c-7pwfn Total loading time: 0 Render date: 2026-11-12T18:06:41.064Z Has data issue: false hasContentIssue false
  • English
  • Français

Turbulence structure near a sharp density interface

Published online by Cambridge University Press:  21 April 2006

Imad A. Hannoun,
Harindra J. S. Fernando and
E. John List
Imad A. Hannoun
Affiliation:
Jaycor, PO Box 85154, San Diego, CA 92138-9259, USA
Harindra J. S. Fernando
Affiliation:
Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287, USA
E. John List
Affiliation:
W. M. Keck Laboratory of Hydraulics and Water Resources, California Institute of Technology, Pasadena, CA 91125, USA
Get accessRights & Permissions [Opens in a new window]

Abstract

The effects of a sharp density interface and a rigid flat plate on oscillating-grid induced shear-free turbulence were investigated experimentally. A two-component laser-Doppler velocimeter was used to measure turbulence intensities in and above the density interface (with matched refractive indices) and near the rigid flat plate. Energy spectra, velocity correlations, and kinetic energy fluxes were also measured. Amplification of the horizontal turbulent velocity, coupled with a sharp reduction in the vertical turbulent velocity, was observed near both the density interface and the flat plate. These findings are in agreement with some previous results pertaining to shear-free turbulence near rigid walls (Hunt & Graham 1978) and near density interfaces (Long 1978). The results imply that, near the density interface, the turbulent kinetic energy in the vertical velocity component is only a small fraction of the total turbulent kinetic energy and indicate that the effects of the anisotropy created by the density interface or the flat plate are confined to the large turbulence scales.

Information

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 189 , April 1988, pp. 189 - 209
Copyright
© 1988 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.)

Article purchase

Temporarily unavailable

References

Crapper, P. E. & Linden, P. F. 1974 The structure of turbulent density interfaces. J. Fluid Mech. 65, 45.Google Scholar
Fernando, H. J. S. & Long, R. R. 1983 The growth of a grid-generated turbulent mixed layer in a two-fluid system. J. Fluid Mech. 133, 377.Google Scholar
Fernando, H. J. S. & Long, R. R. 1985a Mixed-layer growth in stratified fluids. In The Ocean Surface: Wave Breaking, Turbulent Mixing and Radio Probing (ed. Y. Toba & H. Mitsuyasu), p. 541.
Fernando, J. J. S. & Long, R. R. 1985b On the nature of the entrainment interface of a two-layer fluid subjected to zero-mean shear turbulence. J. Fluid Mech. 151, 21.Google Scholar
Fernando, H. J. S. & Long, R. R. 1985c The growth of a shear-free mixed layer in a linearly stratified fluid. Phys. Fluids 28, 2999.Google Scholar
Folse, R. F., Cox, T. P. & Schexnayder, K. R. 1981 Measurements of the growth of a turbulently mixed layer in a linearly stratified fluid. Phys. Fluids. 24, 396.Google Scholar
Gartrell, G. 1979 A signal processor for a laser-Doppler velocimeter. W.M. Keck Laboratory of Hydraulics and Water Resources Tech. Mem. 78–5. California Institute of Technology.
Hannoun, I. A. 1985 Matching the refractive index in density stratified flows. W.M. Keck Laboratory of Hydraulics and Water Resources Tech. Mem. 85-1. California Institute of Technology.
Hopfinger, E. J. & Toly, J. A. 1976 Spatially decaying turbulence and its relation to mixing across density interfaces. J. Fluid Mech. 78, 155.Google Scholar
Hopfinger, E. J. & Linden, P. F. 1982 Formation of thermoclines in zero-mean shear turbulence subjected to a stabilizing buoyancy flux. J. Fluid Mech. 114, 157.Google Scholar
Hunt, J. C. R. 1984 Turbulence structure in thermal convection and shear-free boundary layers. J. Fluid Mech. 138, 161.Google Scholar
Hunt, J. C. R. & Graham, J. M. R. 1978 Free-stream turbulence near plane boundaries. J. Fluid Mech. 84, 209.Google Scholar
Kitaigorodski, S. A. 1979 Review of the theories of wind-mixed layer deepening. Marine Forecasting, Elsevier Oceanographic Ser. 25, 1.Google Scholar
Koochesfahani, M. M. 1984 Experiments on turbulent mixing and chemical reaction in a liquid mixing layer. Ph.D. thesis. California Institute of Technology.
Linden, P. F. 1975 The deepening of a mixed layer in a stratified fluid. J. Fluid Mech. 78, 385.Google Scholar
Liu, H. T., Lin, J. T., Delisi, D. P. & Robben, F. A. 1977 Application of a fluorescence technique to dye-concentration measurements in a turbulent jet. NBS Special Publication 484, in Proc. Symp. on Flow in Open Channels and Closed Conduits held at NBS, Gaithersburg, MD, February 1977.
Long, R. R. 1978 A theory of mixing in stably stratified fluids. J. Fluid Mech. 84, 113.Google Scholar
McDougall, T. J. 1979b On the elimination of refractive index variations in turbulent density stratified flows. J. Fluid Mech. 93, 83.Google Scholar
McDougall, T. J. 1979b Measurements of turbulence in a zero-mean shear mixed layer. J. Fluid Mech. 94, 409.Google Scholar
Papanicolaou, P. N. 1985 Mass and momentum transport in a turbulent buoyant vertical axisymmetric jet. Ph.D thesis. California Institute of Technology.
Papantoniou, D. P. 1986 Observations in turbulent buoyant jets by use of laser-induced fluorescence. Ph.D. thesis. California Institute of Technology.
Phillips, O. M. 1977 Dynamics of the Upper Ocean. Cambridge University Press.
Tennekes, H. 1975 Eulerian and Lagrangian time microscales in isotropic turbulence. J. Fluid Mech. 67, 349.Google Scholar
Thomas, N. H. & Hancock, P. E. 1977 Grid turbulence near a moving wall. J. Fluid Mech. 82, 97.Google Scholar
Thompson, S. M. & Turner, J. S. 1975 Mixing at an interface due to turbulence generated by an oscillating grid. J. Fluid Mech. 67, 349.Google Scholar
Turner, J. S. 1968 The influence of molecular diffusivity on turbulent entrainment across a density interface. J. Fluid Mech. 33, 639.Google Scholar
Turner, J. S. 1979 Buoyancy Effects in Fluids. Cambridge University Press.
Uzkan, T. & Reynolds, W. C. 1967 A shear-free turbulent boundary layer. J. Fluid Mech. 28, 803.Google Scholar
Wang, J. & Wu, J. 1985 Wind induced water turbulence. In The Ocean Surface: Wave Breaking, Turbulent Mixing and Radio Probing, (ed. Y. Toba & H. Mitsuyasu), p. 401.