A general model for the helical structure of geophysical flows in channel bends

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Authors

Maria Azpiroz-Zabala, Matthieu Cartigny, Esther J. Sumner, Michael Clare, Peter J. Talling, Daniel R. Parsons, Cortis Cooper

Abstract

Meandering channels host geophysical flows that form the most extensive sediment transport systems on Earth (i.e. rivers and submarine channels). Measurements of helical flow structures in bends have been key to understanding sediment transport in rivers. Turbidity currents differ from rivers in both density and velocity profiles. These differences, and the lack of field measurements of turbidity currents, have led to multiple models for their helical flow. Here we present the first measurements of helical flows from turbidity currents in the ocean. These ten flows lasted between one and ten days, had up to ~80-metre thickness, and all displayed the same helical structure. This structure comprised two vertically-stacked cells, with the bottom cell rotating with the opposite direction to helical flow in rivers. Furthermore, we propose a general model that predicts the range of helical flow structures observed in rivers, estuaries and turbidity currents based on their density stratification.

DOI

https://doi.org/10.31223/osf.io/pfb7u

Subjects

Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Sciences, Fluid Dynamics, Geology, Geomorphology, Geophysics and Seismology, Hydrology, Life Sciences, Natural Resources and Conservation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Physics, Risk Analysis, Sedimentology

Keywords

ADCP, Turbidity currents, helical flow, Direct observations, Meandering channels, Secondary circulation, Submarine channel systems, Submarine density flows

Dates

Published: 2017-10-31 12:21

License

Academic Free License (AFL) 3.0

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