Self-sharpening induces jet-like structure in seafloor gravity currents
Dorrell, R.M.; Peakall, J.; Darby, S.E.; Parsons, D.R.; Johnson, J.; Summer, E.J.; Wynn, R.B.; Ozsoy, E.; Tezcan, D. (2019). Self-sharpening induces jet-like structure in seafloor gravity currents. Nature Comm. 10(1): 10 pp. https://dx.doi.org/10.1038/s41467-019-09254-2
In: Nature Communications. Nature Publishing Group: London. ISSN 2041-1723; e-ISSN 2041-1723, more
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| Authors | | Top |
- Dorrell, R.M.
- Peakall, J.
- Darby, S.E.
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- Parsons, D.R.
- Johnson, J.
- Summer, E.J.
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- Wynn, R.B.
- Ozsoy, E., more
- Tezcan, D.
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| Abstract |
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. |
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