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dc.contributor.author
Haller, George
dc.contributor.author
Aksamit, Nikolas O.
dc.contributor.author
Encinas-Bartos, Alex P.
dc.date.accessioned
2021-05-05T09:27:07Z
dc.date.available
2021-05-05T04:04:31Z
dc.date.available
2021-05-05T09:27:07Z
dc.date.issued
2021-04
dc.identifier.issn
1054-1500
dc.identifier.issn
1089-7682
dc.identifier.other
10.1063/5.0044151
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/482474
dc.description.abstract
We derive measures of local material stretching and rotation that are computable from individual trajectories without reliance on other trajectories or on an underlying velocity field. Both measures are quasi-objective: they approximate objective (i.e., observer-independent) coherence diagnostics in frames satisfying a certain condition. This condition requires the trajectory accelerations to dominate the angular acceleration induced by the spatial mean vorticity. We illustrate on examples how quasi-objective coherence diagnostics highlight elliptic and hyperbolic Lagrangian coherent structures even from very sparse trajectory data. A vast amount of discrete tracer trajectory data is available for fluid flows in the laboratory and in nature. All features of tracer trajectories, however, including their shape, velocities, and looping, depend on the reference frame of the observer even though the coherent flow structures one often tries to infer from tracers are observer indifferent. Here, we develop quasi-objective coherent structure diagnostics that can be computed from individual single tracer trajectories without reliance on other trajectories. A quasi-objective diagnostic approximates an objective diagnostics in all frames of reference that satisfy certain conditions we derive. We show how the single-trajectory quasi-objective scalar fields highlight material coherent structures even from sparse trajectory data sets on which multi-trajectory objective diagnostics tend to perform poorly.
en_US
dc.language.iso
en
en_US
dc.publisher
AIP Publishing
en_US
dc.title
Quasi-objective coherent structure diagnostics from single trajectories
en_US
dc.type
Journal Article
dc.date.published
2021-04-22
ethz.journal.title
Chaos
ethz.journal.volume
31
en_US
ethz.journal.issue
4
en_US
ethz.journal.abbreviated
Chaos (Woodbury N.Y.)
ethz.pages.start
043131
en_US
ethz.size
17 p.
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Melville, NY
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02618 - Institut für Mechanische Systeme / Institute of Mechanical Systems::03973 - Haller, George / Haller, George
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02618 - Institut für Mechanische Systeme / Institute of Mechanical Systems::03973 - Haller, George / Haller, George
ethz.date.deposited
2021-05-05T04:04:48Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2021-05-05T09:27:25Z
ethz.rosetta.lastUpdated
2021-05-05T09:27:25Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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