Soliton generation by internal tidal beams impinging on a pycnocline: laboratory experiments

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Matthieu J Mercier (Author) Other; Manikandan Mathur (Author) Other; Louis Gostiaux (Author) Other; Theo Gerkema (Author) Other; Jorge M Magalhaes (Author) Other; Jose C B Da Silva (Author) FCUP; Thierry Dauxois (Author) Other

Journal

Title: Journal of Fluid Mechanics

Vol. 704

Pages: 37-60

ISSN: 0022-1120

Publisher: Cambridge University Press

Indexing

ISI Web of Knowledge - 49 Citations

Scopus - 46 Citations

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-002-6ZC

DOI: 10.1017/jfm.2012.191

Abstract (EN): In this paper, we present the first laboratory experiments that show the generation of internal solitary waves by the impingement of a quasi-two-dimensional internal wave beam on a pycnocline. These experiments were inspired by observations of internal solitary waves in the deep ocean from synthetic aperture radar (SAR) imagery, where this so-called mechanism of 'local generation' was argued to be at work, here in the form of internal tidal beams hitting the thermocline. Nonlinear processes involved here are found to be of two kinds. First, we observe the generation of a mean flow and higher harmonics at the location where the principal beam reflects from the surface and pycnocline; their characteristics are examined using particle image velocimetry (PIV) measurements. Second, we observe internal solitary waves that appear in the pycnocline, detected with ultrasonic probes; they are further characterized by a bulge in the frequency spectrum, distinct from the higher harmonics. Finally, the relevance of our results for understanding ocean observations is discussed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 24