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Strong turbulent mixing induced by internal bores interacting with internal tide‐driven vertically sheared flow
Author(s) -
Masunaga Eiji,
Fringer Oliver B.,
Yamazaki Hidekatsu,
Amakasu Kazuo
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl067812
Subject(s) - internal tide , internal wave , turbulence kinetic energy , mixing (physics) , turbulence , dissipation , geology , mechanics , internal flow , flow (mathematics) , kinetic energy , intensity (physics) , physics , optics , classical mechanics , thermodynamics , quantum mechanics
We observed the formation of an internal bore interacting with the vertically sheared flow generated during the previous phase of the internal tide, which resulted in strong turbulent mixing. The rate of turbulent kinetic energy dissipation reached on the order of 10 −5 W kg −1 during the event. Numerical simulations reproduced the observed interaction of internal bores with the sheared flow and verified the hypothesized breaking and mixing mechanism. The numerical results indicated that the Iribarren number, or the ratio of the topographic slope to the internal wave slope, plays a major role in the mixing intensity and types of internal bores. It was found that waves with low Iribarren numbers lead to bores that interact with vertically sheared flows induced by the previous phase of the internal tide and are more likely to produce strong wave breaking and mixing.