000014617 001__ 14617
000014617 005__ 20161115100157.0
000014617 04107 $$aeng
000014617 046__ $$k2016-08-21
000014617 100__ $$aArratia, Cristobal
000014617 24500 $$aTransient growth on time-dependent strongly-stratified flows

000014617 24630 $$n24.$$p24th International Congress of Theoretical and Applied Mechanics - Book of Papers
000014617 260__ $$bInternational Union of Theoretical and Applied Mechanics, 2016
000014617 506__ $$arestricted
000014617 520__ $$2eng$$aWe study the competition between the zigzag instability and Lilly’s mechanism of vertical decorrelation through independentlyevolving horizontal layers by computing the linear optimal perturbations to different types of vertically-invariant base flows with strong stratification. This allows us to find, as a function of vertical wavelength, the potential of linear perturbations to extract energy from each base flow. We observe that the zigzag instability is more relevant than Lilly’s mechanism only when the base flow is composed of distinct vortices, while the zigzag scaling laws remain always valid except for viscous effects. Additionaly, the optimal perturbations reveal other, more efficient mechanisms of transient energy extraction. Performing toroidal-poloidal decomposition of the optimal perturbations we observe that, as the vertical wavenumber increases, the optimal perturbations are increasingly associated to energy extraction from the vertical vorticity into vertical velocity and density perturbations.

000014617 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000014617 653__ $$a

000014617 7112_ $$a24th International Congress of Theoretical and Applied Mechanics$$cMontreal (CA)$$d2016-08-21 / 2016-08-26$$gICTAM2016
000014617 720__ $$aArratia, Cristobal
000014617 8560_ $$ffischerc@itam.cas.cz
000014617 8564_ $$s129878$$uhttps://invenio.itam.cas.cz/record/14617/files/TS.FM09-1.04.pdf$$yOriginal version of the author's contribution as presented on CD,  page 1093, code TS.FM09-1.04
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000014617 962__ $$r13812
000014617 980__ $$aPAPER