Nonlinear internal wave penetration via parametric subharmonic instability
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Author(s) • • • •
Joubaud, S.
Dauxois, T.
Odier, P.
Ghaemsaidi, Sasan John
Peacock, Thomas
Date Issued
January 2016
Journal
Physics of Fluids
Publisher
American Institute of Physics (AIP)
Citation
Ghaemsaidi, S. J., S. Joubaud, T. Dauxois, P. Odier, and T. Peacock. “Nonlinear Internal Wave Penetration via Parametric Subharmonic Instability.” Physics of Fluids 28, no. 1 (January 2016): 011703.
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Author's final manuscript
Abstract
We present the results of a laboratory experimental study of an internal wave field generated by harmonic, spatially periodic boundary forcing from above of a density stratification comprising a strongly stratified, thin upper layer sitting atop a weakly stratified, deep lower layer. In linear regimes, the energy flux associated with relatively high frequency internal waves excited in the upper layer is prevented from entering the lower layer by virtue of evanescent decay of the wave field. In the experiments, however, we find that the development of parametric subharmonic instability in the upper layer transfers energy from the forced primary wave into a pair of subharmonic daughter waves, each capable of penetrating the weakly stratified lower layer. We find that around 10% of the primary wave energy flux penetrates into the lower layer via this nonlinear wave-wave interaction for the regime we study.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1063/1.4939001