Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-19T16:36:04.490Z Has data issue: false hasContentIssue false
  • English
  • Français

Interleaving intrusions produced by internal waves: a laboratory experiment

Published online by Cambridge University Press:  25 April 2008

ROSS W. GRIFFITHS  and
ALI A. BIDOKHTI
ROSS W. GRIFFITHS
Affiliation:
Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia
ALI A. BIDOKHTI
Affiliation:
Institute of Geophysics, Tehran University, Tehran, PO Box 14155-6466, Iran
Get access Rights & Permissions [Opens in a new window]

Abstract

A statically stable stratified water column that also contains horizontal property contrasts (either of passive tracer alone or of two dynamically active solutes) is generated and continuously maintained for a long period by releasing two turbulent buoyant plumes of equal buoyancy fluxes into opposite ends of a long channel of water. The bottom outflows from the plumes also continuously excite internal gravity waves that produce a series of counter-flowing quasi-horizontal shear layers which are quasi-stationary relative to the box but whose phase propagates downward through the upward-moving water column. We report that the flow further involves an oscillation associated with the internal waves that gives rise to a sequence of interleaving intrusions across the horizontal gradient region. The wave-driven intrusions are advected upward with the ‘filling-box’ circulation and have the appearance of a spatially growing instability. The intrusions are examined in cases having no horizontal property differences other than a passive tracer. In further experiments where one plume is salt solution and the other is sugar solution, there is vigorous double-diffusive convection on the interleaving intrusions, including salt fingering and diffusive density interfaces, but this convection has only a weak influence on the intrusion thicknesses and velocities. We conclude that under all conditions attained in these experiments, the interleaving is driven by internal waves and not by the property gradients, and we infer that the wave-generated intrusions enhance double-diffusive buoyancy fluxes.

Type
Papers
Information
Journal of Fluid Mechanics , Volume 602 , 10 May 2008 , pp. 219 - 239
Copyright
Copyright © Cambridge University Press 2008

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

REFERENCES

Baines, W. D. & Turner, J. S. 1969 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 37, 51–80.CrossRefGoogle Scholar
Bidokhti, A. A. 2000 A newly developed low drift fast response salinity meter. Rev. Sci. Instrum. 71, 3539–3542.CrossRefGoogle Scholar
Browand, F. K., Guyomar, D. & Yoon, S.-C. 1987 The behavior of a turbulent front in a stratified fluid: Experiments with an oscillating grid. J. Geophys. Res. 92, 5329–5341.Google Scholar
Chen, C. F. 1974 Onset of cellular convection in a salinity gradient due to a lateral temperature gradient. J. Fluid Mech. 63, 563–576.CrossRefGoogle Scholar
Chen, C. F. & Chen, F. 1997 Salt-finger convection generated by lateral heating of a solute gradient. J. Fluid Mech. 352, 161–176.CrossRefGoogle Scholar
Fedorov, F. N. 1978 The Thermohaline Finestructure of the Ocean. (Translated by Brown, D. A., ed. Turner, J. S.). Pergamon.Google Scholar
Garrett, C. & Munk, W. 1972 Space-time scales of internal waves. Geophys. Fluid Dyn. 2, 225–264.CrossRefGoogle Scholar
Garrett, C. & Munk, W. 1979 Internal waves in the ocean. Annu. Rev. Fluid Mech. 11, 339–369.CrossRefGoogle Scholar
Georgi, D. T. 1978 Fine-structure in the antarctic polar front zone: its characteristics and possible relationship to internal waves. J. Geophys. Res. 83, 4579–4588.CrossRefGoogle Scholar
Hart, J. E. 1973 Finite amplitude sideways diffusive convection. J. Fluid Mech. 59, 47–64.CrossRefGoogle Scholar
Huppert, H. E. & Turner, J. S. 1980 Ice blocks melting into a salinity gradient. J. Fluid Mech. 100, 367–384.CrossRefGoogle Scholar
Jeevaraj, C. G. & Imberger, J. 1991 Experimental study of double-diffusive instability in sidewall heating. J. Fluid Mech. 222, 565–586.CrossRefGoogle Scholar
Josberger, E. G. & Martin, S. 1981 Convection generated by vertical icewalls. J. Fluid Mech. 111, 439–473.CrossRefGoogle Scholar
Malki-Epshtein, L., Phillips, O. M. & Huppert, H. E. 2004 The growth and structure of double-diffusive cells adjacent to a cooled sidewall in a salt-stratified environment. J. Fluid Mech. 518, 347–362.CrossRefGoogle Scholar
Maxworthy, T. 1983 Dynamics of double diffusive gravity currents. J. Fluid Mech. 128, 259–282.CrossRefGoogle Scholar
Nagasaka, M., Nagashima, H. & Yoshida, J. 1995 Double diffusively induced intrusions into a density gradient. In Double-Diffusive Convection (ed. Brandt, A. & Fernando, H. J. S.). American Geophysical Union.Google Scholar
Narusawa, U. & Suzukawa, Y. 1981 Experimental study of double-diffusive cellular convection due to a uniform lateral heat flux. J. Fluid Mech. 113, 387–405.CrossRefGoogle Scholar
Ruddick, B. R. 1985 Momentum transport in thermohaline staircase. J. Geophys. Res. 90, 895–902.CrossRefGoogle Scholar
Ruddick, B. R. 2003 Laboratory studies of interleaving. Prog. Oceanogr. 56, 529–547.CrossRefGoogle Scholar
Ruddick, B. R., Griffiths, R. W. & Symonds, G. 1989 Stresses across double-diffusive interfaces. J. Geophys. Res. 94, 18161–18173.CrossRefGoogle Scholar
Ruddick, B. R., Phillips, O. M. & Turner, J. S. 1999 A laboratory and quantitative model of finite-amplitude thermohaline intrusions. Dyn. Atmos. Oceans 30, 71–99.CrossRefGoogle Scholar
Ruddick, B. R. & Richards, K. 2003 Oceanic thermohaline intrusions: observations. Prog. Oceanogr. 56, 499–527.CrossRefGoogle Scholar
Ruddick, B. R. & Turner, J. S. 1979 The vertical scale of double-diffusive intrusions. Deep-Sea Res. 26A, 903–913.CrossRefGoogle Scholar
Tanny, J. & Tsinober, A. B. 1988 The dynamics and structure of double-diffusive layers in sidewall-heating experiments. J. Fluid Mech. 196, 135–156.CrossRefGoogle Scholar
Thorpe, S. A., Hutt, P. K. & Soulsby, R. 1969 The effect of horizontal gradients on thermohaline convection. J. Fluid Mech. 38, 375–400.CrossRefGoogle Scholar
Turner, J. S. 1978 Double-diffusive intrusions into a density gradient. J. Geophys. Res. 83, 2887–2901.CrossRefGoogle Scholar
Turner, J. S. 1986 Turbulent entrainment the development of the entrainment assumption and its application to geophysical flows. J. Fluid Mech. 173, 431–471.CrossRefGoogle Scholar
Turner, J. S. & Chen, C. F. 1974 Two-dimensional effects in double-diffusive convection. J. Fluid Mech. 63, 577–592.CrossRefGoogle Scholar
Wells, M. G., Griffiths, R. W. & Turner, J. S. 2001 The generation of density fine-structure by salt fingers in a spatially periodic shear. J. Geophys. Res. 106, 7027–7037.CrossRefGoogle Scholar
Wong, A. B. D., Griffiths, R. W. & Hughes, G. O. 2001 Shear layer driven by turbulent plumes. J. Fluid Mech. 434, 209–244.CrossRefGoogle Scholar