<div class="csl-bib-body">
<div class="csl-entry">Thorez, S., Blanckaert, K., Lemmin, U., & Barry, D. (2022, May 27). <i>Evidence and possible causes of velocity pulsing in a turbidity current in Lake Geneva</i> [Conference Presentation]. EGU General Assembly 2022 (EGU 2022), Vienna, Austria. https://doi.org/10.34726/3481</div>
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/148137
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dc.identifier.uri
https://doi.org/10.34726/3481
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dc.description.abstract
Negatively buoyant riverine inflows plunge when entering lakes or reservoirs and form gravity-driven currents near the bed. When a high sediment load causes the density excess, such currents are called turbidity currents. They can supply momentum, heat, oxygen, sediments, nutrients and contaminants to deep lake basins and are the main cause of reservoir storage capacity loss. Even with steady inflow, turbidity currents have been observed to exhibit regularly pulsing velocity patterns, which are likely to enhance mixing between the inflowing and the ambient waters. Previously, literature linked this pulsing to several mechanisms, including interfacial waves such as Kelvin-Helmholtz instabilities and Rayleigh-Taylor instabilities related to surface lobes along the plunge line. However, to our knowledge, field measurements of the latter have not been reported.
In the present study, field measurements of the plunging inflow of the negatively buoyant Rhône River into Lake Geneva (Switzerland/France) were carried out. Vessel-mounted ADCP measurements of the longitudinal flow field of the plunging flow and the subsequent turbidity current were combined with remote time-lapse imagery capturing related surface patterns.
The ADCP measurements confirm that the inflowing river water plunges and forms a turbidity current. At the turbidity current-ambient water interface, regularly spaced “bulges” in the velocity pattern suggest pulsing. Simultaneously taken remote time-lapse images show that at the surface, the inflowing sediment-rich water forms a distinct plume with a triangular shape leading away from the river mouth in the downstream direction towards a sharp tip. At the edge and in the immediate surroundings of this plume, a variety of intermittent lobes and vortical structures whose periodicity might be related to that of the velocity pulsing in the turbidity current, is observed.
en
dc.language.iso
en
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dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
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dc.subject
Turbidity current
en
dc.subject
Gravity current
en
dc.subject
Sediment transport
en
dc.subject
Velocity pulsing
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dc.subject
Remote time-lapse imagery
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dc.title
Evidence and possible causes of velocity pulsing in a turbidity current in Lake Geneva
en
dc.type
Presentation
en
dc.type
Vortrag
de
dc.rights.license
Creative Commons Namensnennung 4.0 International
de
dc.rights.license
Creative Commons Attribution 4.0 International
en
dc.identifier.doi
10.34726/3481
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dc.contributor.affiliation
École Polytechnique Fédérale de Lausanne, Switzerland
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dc.contributor.affiliation
École Polytechnique Fédérale de Lausanne, Switzerland
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dc.rights.holder
Autor_in
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dc.type.category
Conference Presentation
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tuw.researchTopic.id
E4
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tuw.researchTopic.name
Environmental Monitoring and Climate Adaptation
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tuw.researchTopic.value
100
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tuw.publication.orgunit
E222-01 - Forschungsbereich Wasserbau und Umwelthydraulik
