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Mixing in gravity currents

Published online by Cambridge University Press:  08 October 2013

A. T. Fragoso ,
M. D. Patterson  and
J. S. Wettlaufer
A. T. Fragoso
Affiliation:
Yale University, New Haven, CT 06520-8109, USA
M. D. Patterson
Affiliation:
University of Bristol, University Walk, Bristol BS8 1TR, UK
J. S. Wettlaufer
Affiliation:
Yale University, New Haven, CT 06520-8109, USA Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK
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Abstract

We study entrainment in lock-release gravity currents using highly spatially resolved optical transmission experiments and quantitative analysis of the available potential energy of the flow. The principal results provide a resolution to the debate regarding the mechanism and degree of mixing in the head of a gravity current during the slumping phase. The nature of the complex internal mixing structure changes as a bore propagates from the tail to the head of the current during the slumping phase and overtakes its leading edge. We use quantitative methods to identify the connection between dynamics and entrainment and show that its manifestation as examined using different methodologies is the cause of previous contradictory experimental findings. Therefore, we conclude that the two main perspectives previously considered at odds are in accord.

JFM classification

Geophysical and Geological Flows: Gravity currents Mixing: Turbulent mixing
Type
Rapids
Information
Journal of Fluid Mechanics , Volume 734 , 10 November 2013 , R2
Copyright
©2013 Cambridge University Press 

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References

Bonnecaze, R. T., Huppert, H. E. & Lister, J. R. 1993 Particle-driven gravity currents. J. Fluid Mech. 250, 339–369.CrossRefGoogle Scholar
Hacker, J., Linden, P. F. & Dalziel, S. B. 1996 Mixing in lock-release gravity currents. Dyn. Atmos. Oceans 24, 183–195.CrossRefGoogle Scholar
Hallworth, M. A., Huppert, H. E., Phillips, J. C. & Sparks, R. S. J. 1996 Entrainment into two-dimensional and axisymmetric turbulent gravity currents. J. Fluid Mech. 308, 289–311.CrossRefGoogle Scholar
Hallworth, M. A., Phillips, J. C., Huppert, H. E. & Sparks, R. S. J. 1993 Entrainment in turbulent gravity currents. Nature 362, 829–831.CrossRefGoogle Scholar
Hoult, D. P. 1972 Oil spreading on the sea. Annu. Rev. Fluid Mech. 4, 341–368.Google Scholar
Huppert, H. E. 2006 Gravity currents: a personal perspective. J. Fluid Mech. 255, 299–332.Google Scholar
Huppert, H. E. & Simpson, J. E. 1980 The slumping of gravity currents. J. Fluid Mech. 99, 785–799.CrossRefGoogle Scholar
Jackson, R. 2010 Entrainment in turbulent gravity currents. B.S. Thesis, Yale University.Google Scholar
Patterson, M. D., Caulfield, C. P., McElwaine, J. N. & Dalziel, S. B. 2006 Time-dependent mixing in stratified Kelvin–Helmholtz billows: experimental observations. Geophys. Res. Lett. 33, L15608.CrossRefGoogle Scholar
Rottman, J. W. & Simpson, J. E. 1983 Gravity currents produced by instantaneous releases of a heavy fluid in a rectangular channel. J. Fluid Mech. 135, 95–110.Google Scholar
Simpson, J. E. 1972 Effects of the lower boundary on the head effects of the lower boundary on the head effect of the lower boundary on the head of a gravity current. J. Fluid Mech. 53, 759–768.CrossRefGoogle Scholar
Winters, K. B., Lombard, P. N., Riley, J. J. & D’Asaro, E. A. 1995 Available potential energy and mixing in density-stratified fluids. J. Fluid Mech. 289, 115–128.CrossRefGoogle Scholar

Fragoso et al. supplementary movie

Experiment 1, raw image: Water level 10 cm, Aspect Ratio = 0.5, Fractional Depth = 1, Reduced Gravity = 12

Download Fragoso et al. supplementary movie(Video)
Video 1.7 MB

Fragoso et al. supplementary movie

Experiment 2, processed image: Water level 30 cm, Aspect Ratio = 1.5, Fractional Depth = 1, Reduced Gravity = 12

Download Fragoso et al. supplementary movie(Video)
Video 3.6 MB

Fragoso et al. supplementary movie

Experiment 3, processed image: Water level 25 cm, Aspect Ratio = 2.5, Fractional Depth = 1, Reduced Gravity = 12

Download Fragoso et al. supplementary movie(Video)
Video 2.4 MB

Fragoso et al. supplementary movie

Experiment 4, processed image: Water level 15 cm, Aspect Ratio = 0.5, Fractional Depth = 0.67, Reduced Gravity = 12

Download Fragoso et al. supplementary movie(Video)
Video 2.7 MB

Fragoso et al. supplementary movie

Experiment 5, processed image: Water level 30 cm, Aspect Ratio = 0.5, Fractional Depth = 0.33, Reduced Gravity = 12

Download Fragoso et al. supplementary movie(Video)
Video 1.9 MB

Fragoso et al. supplementary movie

Experiment 6, processed image: Water level 20 cm, Aspect Ratio = 1, Fractional Depth = 1, Reduced Gravity = 12

Download Fragoso et al. supplementary movie(Video)
Video 3.1 MB

Fragoso et al. supplementary movie

Experiment 7, processed image: Water level 20 cm, Aspect Ratio = 1, Fractional Depth = 1, Reduced Gravity = 24

Download Fragoso et al. supplementary movie(Video)
Video 2.2 MB

Fragoso et al. supplementary movie

Experiment 8, processed image : Water level 20 cm, Aspect Ratio = 1, Fractional Depth = 1, Reduced Gravity = 36

Download Fragoso et al. supplementary movie(Video)
Video 1.6 MB