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Topographically induced internal solitary waves in a pycnocline: Ultrasonic probes and stereo-correlation measurements

Dossmann, Yvan and Paci, Alexandre and Auclair, Francis and Lepilliez, Mathieu and Cid, Emmanuel Topographically induced internal solitary waves in a pycnocline: Ultrasonic probes and stereo-correlation measurements. (2014) Physics of Fluids, vol. 26 (n 5). ISSN 1070-6631

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Official URL: http://dx.doi.org/10.1063/1.4873202

Abstract

Internal solitary waves (ISWs) are large amplitude stable waves propagating in regions of high density gradients such as the ocean pycnocline. Their dynamics has often been investigated in two-dimensional approaches, however, their three-dimensional evolution is still poorly known. Experiments have been conducted in the large stratified water tank of CNRM-GAME to study the generation of ISWs in two academic configurations inspired by oceanic regimes. First, ultrasonic probes are used to measure the interfacial displacement in the two configurations. In the primary generation case for which the two layers are of constant density, the generation of ISWs is investigated in two series of experiments with varying amplitude and forcing frequency. In the secondary generation case for which the lower layer is stratified, the generation of ISWs from the impact of an internal wave beam on the pycnocline and their subsequent dynamics is studied. The dynamics of ISWs in these two regimes accords well with analytical approaches and numerical simulations performed in analogous configurations. Then, recent developments of a stereo correlation technique are used to describe the three-dimensional structure of propagating ISWs. In the primary generation configuration, small transverse effects are observed in the course of the ISW propagation. In the secondary generation configuration, larger transverse structures are observed in the interfacial waves dynamics. The interaction between interfacial troughs and internal waves propagating in the lower stratified layer are a possible cause for the generation of these structures. The magnitude of these transverse structures is quantified with a nondimensional parameter in the two configurations. They are twice as large in the secondary generation case as in the primary generation case.

Item Type:Article
Additional Information:Thanks to American Institute of Physics editor. The original PDF of the article can be found at Physics of Fluids website : http://scitation.aip.org/content/aip/journal/pof2
HAL Id:hal-01102330
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Australian National University - ANU (AUSTRALIA)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS (FRANCE)
Other partners > Météo France (FRANCE)
Laboratory name:
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Deposited By: Emmanuel CID
Deposited On:12 Jan 2015 11:57

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