Density stratification controls the bedform phase diagram of saline-gravity currents versus open-channel flows

Ohata, Koji; de Cala, Isabel; Dorrell, Robert M.; Naruse, Hajime; McLelland, Stuart J.; Simmons, Stephen M.; McCaffrey, William D.

doi:10.1111/sed.13075

Density stratification controls the bedform phase diagram of saline-gravity currents versus open-channel flows

Ohata, Koji; de Cala, Isabel; Dorrell, Robert M.; Naruse, Hajime; McLelland, Stuart J.; Simmons, Stephen M.; McCaffrey, William D.

Authors

Koji Ohata

Isabel de Cala

Robert M. Dorrell

Hajime Naruse

Professor Stuart McLelland S.J.McLelland@hull.ac.uk
Deputy Director of the Energy and Environment Institute

Dr Steve Simmons S.Simmons@hull.ac.uk
Lecturer in Energy and Environment

William D. McCaffrey

Abstract

Sedimentary bedforms such as ripples and dunes are generated both by river flows and sediment-laden gravity currents. Gravity current deposits are usually parameterized using existing bedform phase diagrams which are based on data from laboratory experiments and field observations of open-channel flows. Yet, it is not evident that open-channel flow bedform phase diagrams are applicable to gravity current deposits. Gravity current hydrodynamics are dependent on vertical density variation, that is density stratification, and therefore are fundamentally different from open-channel flows. New experiments to produce gravity current deposits are conducted and compared to existing open-channel flow data. It is shown that a parameter phase-space based on the lower layer of stratified gravity currents (i.e. that part below the velocity maximum) significantly improves the prediction of bedform type compared to bedform phase diagrams derived from layer-averaged parameters. These results confirm that bedforms produced by gravity currents can only be predicted accurately using the characteristics of the lower layer of stratified flow.

Citation

Ohata, K., de Cala, I., Dorrell, R. M., Naruse, H., McLelland, S. J., Simmons, S. M., & McCaffrey, W. D. (in press). Density stratification controls the bedform phase diagram of saline-gravity currents versus open-channel flows. Sedimentology, https://doi.org/10.1111/sed.13075

Journal Article Type	Article
Acceptance Date	Dec 16, 2022
Online Publication Date	Jan 18, 2023
Deposit Date	Feb 2, 2023
Publicly Available Date	Jan 19, 2024
Journal	Sedimentology
Print ISSN	0037-0746
Publisher	Wiley
Peer Reviewed	Peer Reviewed
DOI	https://doi.org/10.1111/sed.13075
Keywords	Bedforms; Bedform phase diagram; Density stratification; Gravity currents; Open-channel flows
Public URL	https://hull-repository.worktribe.com/output/4189954

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Copyright Statement
This is the peer reviewed version of the following article: Ohata, K., de Cala, I., Dorrell, R.M., Naruse, H., McLelland, S.J., Simmons, S.M. and McCaffrey, W.D. (2023), Density stratification controls the bedform phase diagram of saline-gravity currents versus open-channel flows. Sedimentology , which has been published in final form at https://doi.org/10.1111/sed.13075. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.