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On the formation and propagation of nonlinear internal boluses across a shelf break

  • SUBHAS K. VENAYAGAMOORTHY (a1) and OLIVER B. FRINGER (a1)

Abstract

High-resolution two- and three-dimensional numerical simulations are performed of first-mode internal gravity waves interacting with a shelf break in a linearly stratified fluid. The interaction of nonlinear incident waves with the shelf break results in the formation of upslope-surging vortex cores of dense fluid (referred to here as internal boluses) that propagate onto the shelf. This paper primarily focuses on understanding the dynamics of the interaction process with particular emphasis on the formation, structure and propagation of internal boluses onshelf. A possible mechanism is identified for the excitation of vortex cores that are lifted over the shelf break, from where (from the simplest viewpoint) they essentially propagate as gravity currents into a linearly stratified ambient fluid.

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Borzelli, G. & Ligi, R. 1999 Empirical orthogonal function analysis of sst image series: a physical interpretation. J. Phys. Oceanogr. 16, 682690.
Cacchione, D. & Wunsch, C. 1974 Experimental study of internal waves over a slope. J. Fluid Mech. 66, 223239.
Carter, G. S., Gregg, M. C. & Lien, R.-C. 2005 Internal waves, solitary waves, and mixing on the Monterey Bay shelf. Continental Shelf Res. 25, 14991520.
Craig, P. D. 1985 Internal wave dynamics over coastal topography. PhD thesis, University of Western Australia.
Cui, A. & Street, R. L. 2001 Large-eddy simulation of turbulent rotation convective flow development. J. Fluid Mech. 447, 5384.
Cui, A. & Street, R. L. 2004 Large-eddy simulation of coastal upwelling flow. Environ. Fluid Mech. 4, 197223.
Dauxois, T., Didier, A. & Falcon, E. 2004 Observation of near-critical reflection of internal waves in a stably stratified fluid. Phys. Fluids 16, 19361941.
Dauxois, T. & Young, W. R. 1999 Near-critical reflection of internal waves. J. Fluid Mech. 390, 271295.
Fringer, O. B. & Street, R. L. 2003 The dynamics of breaking progressive interfacial waves. J. Fluid Mech. 494, 319353.
Hártel, C., Meiburg, E. & Necker, F. 2000 Analysis and direct numerical simulation of the flow at a gravity-current head. Part 1. Flow topology and front speed for slip and no-slip boundaries. J. Fluid Mech. 418, 189212.
Ivey, G. N. & Nokes, R. I. 1989 Vertical mixing due to the breaking of critical internal waves on sloping boundaries. J. Fluid Mech. 204, 479500.
Ivey, G. N., Winters, K. B. & DeSilva, I. P. D. Silva, I. P. D. 2000 Turbulent mixing in a sloping benthic boundary layer energized by internal waves. J. Fluid Mech. 418, 5976.
Jeong, J. & Hussain, F. 1995 On the identification of a vortex. J. Fluid Mech. 285, 6994.
Klymak, J. M. & Moum, J. N. 2003 Internal solitary waves of elevation advancing on a shoaling shelf. Geophys. Res. Lett. 30, 2045.
Kundu, P. K. 1990 Fluid Mechanics. Academic.
Kunze, E. & LlewellynSmith, S. G. Smith, S. G. 2004 The role of small-scale topography in turbulent mixing of the global ocean. Oceanography 17, 5564.
Legg, S. & Adcroft, A. 2003 Internal wave breaking at concave and convex continental slopes. J. Phys. Oceanogr. 33, 22242246.
Long, R. R. 1955 Some aspects of the flow of stratified fluids, III. Continuous density gradients. Tellus 7, 341357.
Maxworthy, T., Leilich, J., Simpson, J. E. & Meiburg, E. 2002 The propagation of a gravity current into a linearly stratified fluid. J. Fluid Mech. 453, 371394.
Munk, W. & Wunsch, C. 1998 Abyssal recipes II: energetics of tidal and wind mixing. Deep-Sea Res. 45, 19772010.
Nash, J. D., Kunze, E., Toole, J. M. & Schmitt, R. W. 2004 Internal tide reflection and turbulent mixing on the continental slope. J. Phys. Oceanogr. 34, 11171134.
Phillips, O. M. 1977 The Dynamics of the Upper Ocean. Cambridge University Press.
Simpson, A. E. 1972 Effects of the lower boundary on the head of a gravity current. J. Fluid Mech. 53, 759768.
Simpson, A. E. 1997 Gravity Currents. Cambridge University Press.
Simpson, A. E. & Britter, R. E. 1979 The dynamics of the head of a gravity current advancing over a horizontal surface. J. Fluid Mech. 94, 477495.
Slinn, D. N. & Riley, J. J. 1998 Turbulent dynamics of a critically reflecting internal gravity wave. Theor. Comput. Fluid Dyn. 11, 281303.
Taylor, J. R. 1993 Turbulence and mixing in the boundary layer generated by shoaling internal waves. J. Fluid Mech. 19, 233233.
Thorpe, S. A. 1987 On the reflection of a strain of finite-amplitude internal waves from a uniform slope. J. Fluid Mech. 178, 279302.
Thorpe, S. A. 1992 Thermal fronts caused by internal gravity waves reflecting from a slope. J. Phys. Oceanogr. 22, 105108.
Thorpe, S. A. 1999 The generation of alongslope currents by breaking internal waves. J. Phys. Oceanogr. 29, 2945.
Ungarish, M. 2006 On gravity currents in a linearly stratified ambient: a generalization of Benjamin's steady-state propagation results. J. Fluid Mech. 548, 4968.
Venayagamoorthy, S. K. & Fringer, O. B. 2005 Nonhydrostatic and nonlinear contributions to the energy flux budget in nonlinear internal waves. Geophys. Res. Lett. 32, L15603.
Venayagamoorthy, S. K. & Fringer, O. B. 2006 Numerical simulations of the interaction of internal waves with a shelf break. Phys. Fluids 18 (7), 076603.
Zang, Y. & Street, R. L. 1995 Numerical simulation of coastal upwelling and interfacial instability in a rotating and stratified fluid. J. Fluid Mech. 305, 4775.
Zang, Y., Street, R. L. & Koseff, J. R. 1994 A non-staggered grid, fractional step method for time-dependent incompressible Navier–Stokes equations in curvilinear coordinates. J. Comput. Phys. 114, 1833.
Zedler, E. A. & Street, R. L. 2001 Large-eddy simulation of sediment transport: currents over ripples. J. Hydraul. Engng ASCE 127, 442452.
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On the formation and propagation of nonlinear internal boluses across a shelf break

  • SUBHAS K. VENAYAGAMOORTHY (a1) and OLIVER B. FRINGER (a1)

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