Kelly, RW orcid.org/0000-0003-3404-1743, Dorrell, RM, Burns, AD orcid.org/0000-0002-3448-7510 et al. (1 more author) (2019) The Structure and Entrainment Characteristics of Partially Confined Gravity Currents. Journal of Geophysical Research: Oceans, 124 (3). pp. 2110-2125. ISSN 2169-9291
Abstract
Seafloor channels are the main conduit for turbidity currents transporting sediment to the deep ocean, and they can extend for thousands of kilometers along the ocean floor. Although it is common for channel‐traversing turbidity currents to spill onto levees and other out‐of‐channel areas, the associated flow development and channel‐current interaction remain poorly understood; much of our knowledge of turbidity current dynamics comes from studies of fully confined scenarios. Here we investigate the role that partial lateral confinement may play in affecting turbidity current dynamics. We report on laboratory experiments of partially confined, dilute saline flows of variable flux rate traversing fixed, straight channels with cross‐sectional profiles representative of morphologies found in the field. Complementary numerical experiments, validated against high‐resolution laboratory velocity data, extend the scope of the analysis. The experiments show that partial confinement exerts a first‐order control on flow structure. Overbank and downstream discharges rapidly adjust over short length scales, providing a mechanism via which currents of varying sizes can be tuned by a channel and conform to a given channel geometry. Across a wide range of flow magnitudes and states of flow equilibration to the channel, a high‐velocity core remains confined within the channel with a constant ratio of velocity maximum height to channel depth. Ongoing overbank flow prevents any flow thickening due to ambient entrainment, allowing stable downstream flow evolution. Despite dynamical differences, the entrainment rates of partially confined and fully confined flows remain comparable for a given Richardson number.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | ©2019. American Geophysical Union. This is an author produced version of an article published in Journal of Geophysical Research: Oceans. Uploaded in accordance with the publisher's self-archiving policy. This is the pre-peer reviewed version of the following article: Kelly, R. W., Dorrell, R. M., Burns, A. D., & McCaffrey, W. D. ( 2019). The structure and entrainment characteristics of partially confined gravity currents. Journal of Geophysical Research: Oceans, 124, 2110– 2125, which has been published in final form at https://doi.org/10.1029/2018JC014042. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions |
Keywords: | gravity current; turbidity; CFD; fluid dynamics |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 08 Mar 2019 11:48 |
Last Modified: | 17 Dec 2024 12:20 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1029/2018JC014042 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:143400 |