Flow dynamics and mixing processes in hydraulic jump arrays: Implications for channel-lobe transition zones


Dorrell, R.M., Peakall, J., Sumner, E.J., Parsons, D.R., Darby, S.E., Wynn, R.B., Ozsoy, E. and Tezcan, D. (2016) Flow dynamics and mixing processes in hydraulic jump arrays: Implications for channel-lobe transition zones Marine Geology, 381, pp. 181-193. (doi:10.1016/j.margeo.2016.09.009).

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Description/Abstract

A detailed field investigation of a saline gravity current in the southwest Black Sea has enabled the first complete analysis of three-dimensional flow structure and dynamics of a series of linked hydraulic jumps in stratified, density-driven, flows. These field observations were collected using an acoustic Doppler current profiler mounted on an autonomous underwater vehicle, and reveal that internal mixing processes in hydraulic jumps, including flow expansion and recirculation, provide a previously unrecognised mechanism for grain-size sorting and segregation in stratified density-driven flows. Field observations suggest a newly identified type of hydraulic jump, that is a stratified low Froude number (< 1.5–2) subaqueous hydraulic jump, with an enhanced ability to transport sediment downstream of the jump, in comparison to hydraulic jumps in other subaerial and submarine flows. These novel field data underpin a new process-based conceptual model of channel lobe transition zones (CLTZs) that explains the scattered offset nature of scours within such settings, the temporal variations in infill and erosion between adjacent scours, how bed shear stresses are maintained across the CLTZ, and why the locus of deposition is so far downstream of the scour zone.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1016/j.margeo.2016.09.009
ISSNs: 0025-3227 (print)
Keywords: Gravity currents, Hydraulic jumps, Stratification, Channel-lobe transition zone
Organisations: Geology & Geophysics, Marine Geoscience, Earth Surface Dynamics
ePrint ID: 401024
Date :
Date Event
18 September 2016Accepted/In Press
20 September 2016e-pub ahead of print
1 November 2016Published
Date Deposited: 03 Oct 2016 13:02
Last Modified: 17 Apr 2017 01:28
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/401024

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