A unifying computational fluid dynamics investigation on the river-like to river-reversed secondary circulation in submarine channel bends

Serchi, F. Giorgio; Peakall, Jeff; Ingham, D.B.; Burns, A. D.

doi:10.1029/2010jc006361

Cited by 31 publications

(52 citation statements)

References 65 publications

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“…4c). Our suggested model contrasts with earlier models that proposed switching of secondary flow direction occurred between bends (Giorgio Serchi et al, 2011;Peakall and Sumner, 2015). Also, rather than reversing the original direction of the flow cell, this process spawns a new river-reversed near-bed flow cell, which is located beneath the original river-like flow cell (Nidzieko et al, 2009).…”

Section: Application Of Saline Flow Model To Our Observationscontrasting

confidence: 85%

“…Our new model differs from previous models (Giorgio Serchi et al, 2011;Dorrell et al, 2013;Peakall and Sumner, 2015) with respect to (i) the location in the channel system where a second basal cell develops, and (ii) the importance of confinement in secondary circulation. In addition, our new model predicts the helical flow structure across a diverse array of particle laden or saline flow types.…”

Section: Application Of the General Model To A Range Of Geophysical Fmentioning

confidence: 91%

“…However, the first physical experiments of helical circulation in turbidity currents showed an opposite direction of rotation -with the near-bed flow moving towards the outer bank (Corney et al, 2006;Keevil et al, 2006). To complicate matters further, both directions of helical circulation (river-like and river-reversed) have subsequently been observed in turbidity current experiments and models, depending on flow conditions and channel morphology (Imran et al, 2007;Islam and Imran, 2008;Cossu and Wells, 2010;Abad et al, 2011;Giorgio Serchi et al, 2011;Huang et al, 2012;Dorrell et al, 2013;Janocko et al, 2013;Bolla Pittaluga and Imran, 2014;Ezz and Imran, 2014).…”

Section: Introductionmentioning

confidence: 99%

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

Azpiroz-Zabala¹,

Cartigny²,

Sumner³

et al. 2017

Preprint

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Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record.  First direct measurements of the helical flow structure of turbidity currents as they travel around a bend. Turbidity currents of different thicknesses and velocities exhibit the same helical flow structure. We reconcile current controversy with a new model that explains helical flow structure for a wide range of geophysical flows.© 2017 American Geophysical Union. All rights reserved. AbstractMeandering channels formed by geophysical flows (e.g. rivers and seafloor turbidity currents) include the most extensive sediment transport systems on Earth. Previous measurements from rivers show how helical flow at meander bends plays a key role in sediment transport and deposition. Turbidity currents differ from rivers in both density and velocity profiles. These differences, and the lack of field measurements from turbidity currents, have led to multiple models for their helical flow around bends. Here we present the first measurements of helical flow in submarine turbidity currents. These ten flows lasted for 1-to-10 days, were up to ~80-metres thick, and displayed a consistent 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.

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Section: Application Of Saline Flow Model To Our Observationscontrasting

confidence: 85%

Section: Application Of the General Model To A Range Of Geophysical Fmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Azpiroz-Zabala¹,

Cartigny²,

Sumner³

et al. 2017

Preprint

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“…A combination of laboratory experiments and numerical analysis has determined what controls the sense of secondary (across-channel) circulation in dilute flows, and whether it is reversed with respect to subaerial river bends. These controls include the height of the velocity maximum and Froude number (e.g., Corney et al 2006;Imran et al 2007;Peakall et al 2007;Abad et al 2011;Giorgio Serchi et al 2011;Abd El-Gawad et al 2012;Huang et al 2012;Dorrell et al 2013b;Sumner et al 2014). At least in some cases, the sense of secondary circulation is reversed with respect to that seen in river bends, as confirmed by recent ADCP measurements from saline underflows that enter the Black Sea (Parsons et al 2011;Sumner et al 2014).…”

Section: (D) Submarine Channels: Flow Dynamics and Deposit Architecturementioning

confidence: 88%

Key Future Directions For Research On Turbidity Currents and Their Deposits

Talling

Allin

Armitage

et al. 2015

Journal of Sedimentary Research

166

117

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Turbidity currents, and other types of submarine sediment density flow, redistribute more sediment across the surface of the Earth than any other sediment flow process, yet their sediment concentration has never been measured directly in the deep ocean. The deposits of these flows are of societal importance as imperfect records of past earthquakes and tsunamogenic landslides and as the reservoir rocks for many deep-water petroleum accumulations. Key future research directions on these flows and their deposits were identified at an informal workshop in September 2013. This contribution summarizes conclusions from that workshop, and engages the wider community in this debate. International efforts are needed for an initiative to monitor and understand a series of test sites where flows occur frequently, which needs coordination to optimize sharing of equipment and interpretation of data. Direct monitoring observations should be combined with cores and seismic data to link flow and deposit character, whilst experimental and numerical models play a key role in understanding field observations. Such an initiative may be timely and feasible, due to recent technological advances in monitoring sensors, moorings, and autonomous data recovery. This is illustrated here by recently collected data from the Squamish River delta, Monterey Canyon, Congo Canyon, and offshore SE Taiwan. A series of other key topics are then highlighted. Theoretical considerations suggest that supercritical flows may often occur on gradients of greater than , 0.6u. Trains of up-slope-migrating bedforms have recently been mapped in a wide range of marine and freshwater settings. They may result from repeated hydraulic jumps in supercritical flows, and dense (greater than approximately 10% volume) near-bed layers may need to be invoked to explain transport of heavy (25 to 1,000 kg) blocks. Future work needs to understand how sediment is transported in these bedforms, the internal structure and preservation potential of their deposits, and their use in facies prediction. Turbulence damping may be widespread and commonplace in submarine sediment density flows, particularly as flows decelerate, because it can occur at low (, 0.1%) volume concentrations. This could have important implications for flow evolution and deposit geometries. Better quantitative constraints are needed on what controls flow capacity and competence, together with improved constraints on bed erosion and sediment resuspension. Recent advances in understanding dilute or mainly saline flows in submarine channels should be extended to explore how flow behavior changes as sediment concentrations increase. The petroleum industry requires predictive models of longer-term channel system behavior and resulting deposit architecture, and for these purposes it is important to distinguish between geomorphic and stratigraphic surfaces

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“…There are very few active channel datasets available to assess factors controlling submarine channel evolution (cf. Serchi et al 2011) and, therefore, this area of research has relied heavily on the study of rock outcrops (e.g. Gardner et al 2003), as well as on mathematical models (Serchi et al 2011) and laboratory studies in flumes ).…”

Section: Introductionmentioning

confidence: 99%

Submarine channel evolution: active channels in fjords, British Columbia, Canada

et al. 2012

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Seafloor channel systems are well developed in several British Columbia (Canada) fjords, including Knight, Bute and Toba inlets. The channels are active conduits for turbidity currents during episodic failures of delta fronts at the fjord heads. Recently acquired swath multibeam bathymetric data enabled a complete and detailed assessment of the form of these channel systems. Repeated multibeam surveys in Bute and Toba inlets (Mar. 2008 and Nov. 2010) indicate that the deeply incised channels may undergo accretion or erosion over a period as short as 2.5 years. Locally significant (>15 m) bathymetric changes were documented in the channel systems, with bathymetric differences exceeding 5 m occurring along approx. 20

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A unifying computational fluid dynamics investigation on the river-like to river-reversed secondary circulation in submarine channel bends

Cited by 31 publications

References 65 publications

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

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

Key Future Directions For Research On Turbidity Currents and Their Deposits

Submarine channel evolution: active channels in fjords, British Columbia, Canada

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