Self-sharpening induces jet-like structure in seafloor gravity currents

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s41467-019-09254-2.pdf

Date

2019-03-27

Author

Dorrell, R. M.
Peakall, J.
Darby, S. E.
Parsons, D. R.
Johnson, J.
Sumner, E. J.
Wynn, R. B.
Ozsoy, E.
Tezcan, Devrim

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Gravity currents are the primary means by which sediments, solutes and heat are transported across the ocean-floor. Existing theory of gravity current flow employs a statistically-stable model of turbulent diffusion that has been extant since the 1960s. Here we present the first set of detailed spatial data from a gravity current over a rough seafloor that demonstrate that this existing paradigm is not universal. Specifically, in contrast to predictions from turbulent diffusion theory, self-sharpened velocity and concentration profiles and a stable barrier to mixing are observed. Our new observations are explained by statistically-unstable mixing and self-sharpening, by boundary-induced internal gravity waves; as predicted by recent advances in fluid dynamics. Self-sharpening helps explain phenomena such as ultra-long runout of gravity currents and restricted growth of bedforms, and highlights increased geohazard risk to marine infrastructure. These processes likely have broader application, for example to wave-turbulence interaction, and mixing processes in environmental flows.

Subject Keywords

Turbİdİty currents, Laboratory analog, Stratİfİed fluİd, Waves, Sedİment, Evolutİon, Dynamİcs, Velocİty, Layers, Entraİnment

URI

https://hdl.handle.net/11511/30030

Journal

NATURE COMMUNICATIONS

DOI

https://doi.org/10.1038/s41467-019-09254-2

Collections

Graduate School of Marine Sciences, Article

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Citation Formats

R. M. Dorrell et al., “Self-sharpening induces jet-like structure in seafloor gravity currents,” NATURE COMMUNICATIONS, pp. 0–0, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/30030.