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A laboratory simulation of mixing across tidal fronts

Published online by Cambridge University Press:  26 April 2006

P. J. Thomas  and
P. F. Linden
P. J. Thomas
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK Present address: Department of Engineering, University of Wanvick, Coventry CV4 7AL, UK; e-mail: pjt@eng.warwick.ac.uk.
P. F. Linden
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK
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Abstract

A laboratory study which simulates the dynamics of shallow sea fronts and the mixing across a tidal front is described. The experiments show, for the first time, that it is possible to simulate a stationary tidal front with the inclusion of buoyancy effects, Coriolis effects and turbulence in the laboratory. Experimental data obtained for the cross-front mixing rate are presented. The data analysis shows that the mixing rate increases with stratification and decreases with rotation. A theoretical model of the flow which collapses the experimental data is developed which shows that the cross-front mixing is controlled by baroclinic processes. The model enables an extrapolation of the laboratory results to oceanographic conditions. Estimates of the cross-front mixing velocity for oceanographic conditions give values consistent with estimates obtained from North Sea data.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 309 , 25 February 1996 , pp. 321 - 344
Copyright
© 1996 Cambridge University Press

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References

Dalziel, S. 1994 Diglmage, Image Processing for Fluid Mechanics, System Overview. Cambridge Environmental Research Consultants Ltd., Cambridge, UK.
Fernando, H. J. S. 1991 Turbulent mixing in stratified fluids. Ann. Rev. Fluid Mech. 23, 455–493.Google Scholar
Fleury, M., Mory, M., Hopfinger, E. J. & Auchere, A. 1991 Effects of rotation on turbulent mixing across a density interface. J. Fluid Mech. 223, 165–191.Google Scholar
Garrett, C. J. R. & Lodder, J. W. 1981 Dynamical aspects of of shallow sea fronts. Phil. Trans. R. Soc. Lond. A 302, 563–581.Google Scholar
Griffiths, R. W. & Hopfinger, E. J. 1984 The structure of mesoscale turbulence and horizontal spreading at ocean fronts. Deep-Sea Res. 31, 245–269.Google Scholar
Griffiths, R. W. & Linden, P. F. 1981 The stability of vortices in a rotating, stratified fluid. J. Fluid Mech. 105, 283–316.Google Scholar
Hill, A. E., James, I. D., Linden, P. F. et al. 1993 Dynamics of tidal mixing fronts in the North Sea. Phil. Trans. R. Soc. Lond. A 343, 431–446.Google Scholar
Holford, J. M. 1994 The evolution of a front. PhD thesis, University of Cambridge, UK.
Ivey, G. N. 1987 Boundary mixing in a rotating, stratified fluid. J. Fluid Mech. 183, 25–44.Google Scholar
James, I. D. 1983 A three-dimensional model of shallow-sea fronts. In North Sea Dynamics (ed.J. Siindermann & W. Lenz). Springer-Verlag.
James, I. D. 1990 Numerical modelling of density-driven circulation in shelf seas. In Modelling Marine Systems, vol. II (ed . A. M. Davies), pp. 345–372. CRC Press.
Le Fégvre, J. 1986 Aspects of the biology of frontal systems. Adv. Mar. Biol. 23, 164–299.Google Scholar
Linden, P. F. 1991 Dynamics of eddies and fronts. In Proc. Enrico Fermi Summer School on ‘Nonlinear Topics in Ocean Physics’ (ed. A. Osborne).
Munk, W 1966 Abyssal recipes. Deep-Sea Res. 13, 707–730.Google Scholar
Pingree, R. D. 1978 Cyclonic eddies and cross-frontal mixing. J. Mar. Biol. Assoc. UK 58, 955–963.Google Scholar
Pingree, R. D. 1979 Baroclinic eddies bordering the Celtic Sea in late summer. J. Mar. Biol. Assoc. UK 59, 689–698.Google Scholar
Pingree, R. D. & Griffiths, D. K. 1978 Tidal fronts on the shelf seas around the British Isles. J. Geophys. Res. 83, 4615–4622.Google Scholar