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Influence of Coriolis force upon bottom boundary layers in a large‐scale gravity current experiment: Implications for evolution of sinuous deep‐water channel systems

Davarpanah Jazi, S.; Wells, M.G.; Peakall, J.; Dorrell, R.M.; Thomas, R.E.; Keevil, G.M.; Darby, S.E.; Sommeria, J.; Viboud, S.; Valran, T.

Authors

S. Davarpanah Jazi

M.G. Wells

J. Peakall

Dr Robert Thomas R.E.Thomas@hull.ac.uk
Senior Research Fellow in Geomorphology and Flood Risk

G.M. Keevil

S.E. Darby

J. Sommeria

S. Viboud

T. Valran



Abstract

Oceanic density currents in many deep-water channels are strongly influenced by the Coriolis force. The dynamics of the bottom-boundary layer in large geostrophic flows, and low Rossby number turbidity currents, are very important for determining the erosion and deposition of sediment in channelized contourite currents and many large-scale turbidity currents. However, these bottom boundary layers are notoriously difficult to resolve with oceanic field measurements, or in previous small-scale rotating laboratory experiments. We present results from a large, 13 m diameter, rotating laboratory platform that is able to achieve both stratified and highly turbulent flows in regimes where the rotation is sufficiently rapid that the Coriolis force can potentially dominate. By resolving the dynamics of the turbulent bottom boundary in straight and sinuous channel sections, we find that the Coriolis force can overcome centrifugal force to switch the direction of near-bed flows in channel bends. This occurs for positive Rossby numbers less than +0.8, defined as RoR =

Journal Article Type Article
Journal Journal of Geophysical Research: Oceans
Print ISSN 2169-9275
Electronic ISSN 2169-9291
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
APA6 Citation Davarpanah Jazi, S., Wells, M., Peakall, J., Dorrell, R., Thomas, R., Keevil, G., …Valran, T. (in press). Influence of Coriolis force upon bottom boundary layers in a large‐scale gravity current experiment: Implications for evolution of sinuous deep‐water channel systems. Journal of geophysical research. C, Oceans, https://doi.org/10.1029/2019jc015284
DOI https://doi.org/10.1029/2019jc015284
Keywords Gravity currents; Coriolis force; Centrifugal force; Sinuous submarine channels; Ekman boundary layers; Laboratory experiments
Additional Information Received: 2019-05-13; Accepted: 2020-02-01; Published: 2020-02-10