Low-mode internal tide generation by topography: an experimental and numerical investigation
Author(s)Echeverri, Paula; Flynn, Morris R.; Winters, Kraig B.; Peacock, Thomas
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We analyse the low-mode structure of internal tides generated in laboratory experiments and numerical simulations by a two-dimensional ridge in a channel of finite depth. The height of the ridge is approximately half of the channel depth and the regimes considered span sub- to supercritical topography. For small tidal excursions, of the order of 1% of the topographic width, our results agree well with linear theory. For larger tidal excursions, up to 15% of the topographic width, we find that the scaled mode 1 conversion rate decreases by less than 15%, in spite of nonlinear phenomena that break down the familiar wave-beam structure and generate harmonics and inter-harmonics. Modes two and three, however, are more strongly affected. For this topographic configuration, most of the linear baroclinic energy flux is associated with the mode 1 tide, so our experiments reveal that nonlinear behaviour does not significantly affect the barotropic to baroclinic energy conversion in this regime, which is relevant to large-scale ocean ridges. This may not be the case, however, for smaller scale ridges that generate a response dominated by higher modes.
DepartmentMassachusetts Institute of Technology. Department of Mathematics; Massachusetts Institute of Technology. Department of Mechanical Engineering
Journal of Fluid Mechanics
Cambridge University Press
Echeverri, Paula et al. (2009). "Low-mode internal tide generation by topography: an experimental and numerical investigation." Journal of Fluid Mechanics, 636, pp 91-108 © Cambridge University Press 2009.
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