Skip to main content Accessibility help
×
Home

Interleaving intrusions produced by internal waves: a laboratory experiment

  • ROSS W. GRIFFITHS (a1) and ALI A. BIDOKHTI (a2)

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.

Copyright

References

Hide All
Baines, W. D. & Turner, J. S. 1969 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 37, 5180.
Bidokhti, A. A. 2000 A newly developed low drift fast response salinity meter. Rev. Sci. Instrum. 71, 35393542.
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, 53295341.
Chen, C. F. 1974 Onset of cellular convection in a salinity gradient due to a lateral temperature gradient. J. Fluid Mech. 63, 563576.
Chen, C. F. & Chen, F. 1997 Salt-finger convection generated by lateral heating of a solute gradient. J. Fluid Mech. 352, 161176.
Fedorov, F. N. 1978 The Thermohaline Finestructure of the Ocean. (Translated by Brown, D. A., ed. Turner, J. S.). Pergamon.
Garrett, C. & Munk, W. 1972 Space-time scales of internal waves. Geophys. Fluid Dyn. 2, 225264.
Garrett, C. & Munk, W. 1979 Internal waves in the ocean. Annu. Rev. Fluid Mech. 11, 339369.
Georgi, D. T. 1978 Fine-structure in the antarctic polar front zone: its characteristics and possible relationship to internal waves. J. Geophys. Res. 83, 45794588.
Hart, J. E. 1973 Finite amplitude sideways diffusive convection. J. Fluid Mech. 59, 4764.
Huppert, H. E. & Turner, J. S. 1980 Ice blocks melting into a salinity gradient. J. Fluid Mech. 100, 367384.
Jeevaraj, C. G. & Imberger, J. 1991 Experimental study of double-diffusive instability in sidewall heating. J. Fluid Mech. 222, 565586.
Josberger, E. G. & Martin, S. 1981 Convection generated by vertical icewalls. J. Fluid Mech. 111, 439473.
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, 347362.
Maxworthy, T. 1983 Dynamics of double diffusive gravity currents. J. Fluid Mech. 128, 259282.
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.
Narusawa, U. & Suzukawa, Y. 1981 Experimental study of double-diffusive cellular convection due to a uniform lateral heat flux. J. Fluid Mech. 113, 387405.
Ruddick, B. R. 1985 Momentum transport in thermohaline staircase. J. Geophys. Res. 90, 895902.
Ruddick, B. R. 2003 Laboratory studies of interleaving. Prog. Oceanogr. 56, 529547.
Ruddick, B. R., Griffiths, R. W. & Symonds, G. 1989 Stresses across double-diffusive interfaces. J. Geophys. Res. 94, 1816118173.
Ruddick, B. R., Phillips, O. M. & Turner, J. S. 1999 A laboratory and quantitative model of finite-amplitude thermohaline intrusions. Dyn. Atmos. Oceans 30, 7199.
Ruddick, B. R. & Richards, K. 2003 Oceanic thermohaline intrusions: observations. Prog. Oceanogr. 56, 499527.
Ruddick, B. R. & Turner, J. S. 1979 The vertical scale of double-diffusive intrusions. Deep-Sea Res. 26A, 903913.
Tanny, J. & Tsinober, A. B. 1988 The dynamics and structure of double-diffusive layers in sidewall-heating experiments. J. Fluid Mech. 196, 135156.
Thorpe, S. A., Hutt, P. K. & Soulsby, R. 1969 The effect of horizontal gradients on thermohaline convection. J. Fluid Mech. 38, 375400.
Turner, J. S. 1978 Double-diffusive intrusions into a density gradient. J. Geophys. Res. 83, 28872901.
Turner, J. S. 1986 Turbulent entrainment the development of the entrainment assumption and its application to geophysical flows. J. Fluid Mech. 173, 431471.
Turner, J. S. & Chen, C. F. 1974 Two-dimensional effects in double-diffusive convection. J. Fluid Mech. 63, 577592.
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, 70277037.
Wong, A. B. D., Griffiths, R. W. & Hughes, G. O. 2001 Shear layer driven by turbulent plumes. J. Fluid Mech. 434, 209244.
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed