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

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

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.

Citation

Dorrell, R. M., Peakall, J., Darby, S. E., Parsons, D. R., Johnson, J., Sumner, E. J., Wynn, R. B., Özsoy, E., & Tezcan, D. (2019). Self-sharpening induces jet-like structure in seafloor gravity currents. Nature communications, 10(1), Article 1381. https://doi.org/10.1038/s41467-019-09254-2

• Journal Article Type: Article
• Acceptance Date: Feb 26, 2019
• Online Publication Date: Mar 27, 2019
• Publication Date: 2019-12
• Deposit Date: Mar 28, 2019
• Publicly Available Date: Mar 29, 2019
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Issue: 1
• Article Number: 1381
• DOI: https://doi.org/10.1038/s41467-019-09254-2
• Keywords: General Biochemistry, Genetics and Molecular Biology; General Physics and Astronomy; General Chemistry
• Public URL: https://hull-repository.worktribe.com/output/1442763
• Publisher URL: https://www.nature.com/articles/s41467-019-09254-2
• Contract Date: Mar 29, 2019