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A subcritical instability of wave-driven alongshore currents

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dc.contributor Universitat de Vic. Escola Politècnica Superior
dc.contributor Universitat de Vic. Grup de Recerca en Medi Ambient i Alimentació
dc.contributor.author Dodd, Nick
dc.contributor.author Iranzo, Vicente
dc.contributor.author Caballeria, Miquel
dc.date.accessioned 2012-10-09T06:52:46Z
dc.date.available 2012-10-09T06:52:46Z
dc.date.created 2001
dc.date.issued 2004
dc.identifier.citation DODD, N.; IRANZO, V.; CABALLERIA SURIÑACH, Miquel. "A subcritical instability of wave-driven alongshore currents". A: Journal of Geophysical Research-Oceans, 2004, vol. 109, núm. C2, pàg. C02018. doi :IO.l029/2001JC001106
dc.identifier.issn 0148–0227
dc.identifier.uri http://hdl.handle.net/10854/1895
dc.description.abstract The development of shear instabilities of a wave-driven alongshore current is investigated. In particular, we use weakly nonlinear theory to investigate the possibility that such instabilities, which have been observed at various sites on the U.S. coast and in the laboratory, can grow in linearly stable flows as a subcritical bifurcation by resonant triad interaction, as first suggested by Shrira eta/. [1997]. We examine a realistic longshore current profile and include the effects of eddy viscosity and bottom friction. We show that according to the weakly nonlinear theory, resonance is possible and that these linearly stable flows may exhibit explosive instabilities. We show that this phenomenon may occur also when there is only approximate resonance, which is more likely in nature. Furthermore, the size of the perturbation that is required to trigger the instability is shown in some circumstances to be consistent with the size of naturally occurring perturbations. Finally, we consider the differences between the present case examined and the more idealized case of Shrira et a/. [ 1997]. It is shown that there is a possibility of coupling between triads, due to the richer modal structure in more realistic flows, which may act to stabilize the flow and act against the development of subcritical bifurcations. Extensive numerical tests are called for. ca_ES
dc.format application/pdf
dc.format.extent 19 p. ca_ES
dc.language.iso eng ca_ES
dc.publisher American Geophyisical Union ca_ES
dc.rights (c) American Geophysical Union, 2004
dc.rights Tots els drets reservats ca_ES
dc.subject.other Oceanografia ca_ES
dc.subject.other Geofísica ca_ES
dc.title A subcritical instability of wave-driven alongshore currents ca_ES
dc.type info:eu-repo/semantics/article ca_ES
dc.identifier.doi https://doi.org/IO.l029/2001JC001106
dc.rights.accessRights info:eu-repo/semantics/openAccess
dc.type.version info:eu-repo/semantics/publishedVersion
dc.indexacio Indexat a SCOPUS
dc.indexacio Indexat a WOS/JCR ca_ES

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