Stability of Quasi-Two-Dimensional Vortices

Chomaz, Jean-Marc; Ortiz, Sabine; Gallaire, François; Billant, Paul

doi:10.1007/978-3-642-11587-5_2

Cited by 5 publications

References 44 publications

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“…Clearly, such descriptions are mostly qualitative and sometimes even speculative, but nevertheless, we are making an attempt to provide some more insight into this question. First we note that results obtained for instabilities of inviscid vortices (Godeferd et al, 2001;Chomaz et al, 2010;Carnevale et al, 2016), as well as for inviscid vortex pairs (Billant, 1999;Roy et al, 2008;Leweke et al, 2016), in an unbounded domain, cannot be applied for the bounded viscous flow considered here. Moreover, in the present helical pipe configuration, the flow through the pipe and the secondary Dean vortices are already interconnected in the base flow, contrarily to inviscid vortices superimposed with axial flow (e.g., Roy et al, 2008) or with background rotation (e.g., Godeferd et al, 2001;Gargan-Shingles, 2016).…”

Section: Classification and Description Of The Unstable Eigenmodesmentioning

confidence: 97%

A comparative study on instability of steady flows in helical pipes

Gelfgat¹,

Gelfgat²

2020

Fluid Dyn. Res.

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A parametric numerical study of three-dimensional instability of steady flows in a helical pipe of arbitrary curvature and torsion is carried out. The computations are performed by a numerical approach verified against independent experimental and numerical results in a previous study.The results are reported as dependences of the critical Reynolds number, critical wavenumber and the critical frequency on the dimensionless pipe curvature and torsion. A multiplicity of different disturbance modes becoming most unstable at different values of the governing parameters, is observed. Patterns of the most unstable modes are reported and classified. Different routes to instability including viscous and inviscid mechanisms, locally developing boundary and mixing layers, interaction between the Dean vortices and the through flow are described.

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Section: Classification and Description Of The Unstable Eigenmodesmentioning

confidence: 97%

A comparative study on instability of steady flows in helical pipes

Gelfgat¹,

Gelfgat²

2020

Fluid Dyn. Res.

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“…It is worth recalling that centrifugal instability and Coriolis shear instability correspond here to the same phenomenon, as both refer to the same criterion, e.g. Chomaz et al (2010), although the Coriolis shear mechanism is more generally invoked in a rotating reference frame.…”

Section: Inertial Instabilitymentioning

confidence: 98%

Instabilities and small-scale waves within the Stewartson layers of a thermally driven rotating annulus

Larcher¹,

Viazzo²,

Harlander³

et al. 2018

J. Fluid Mech.

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We report on small-scale instabilities in a thermally driven rotating annulus filled with a liquid with moderate Prandtl number. The study is based on direct numerical simulations and an accompanying laboratory experiment. The computations are performed independently with two different flow solvers, that is, first, the non-oscillatory forward-in-time differencing flow solver EULAG and, second, a higher-order finite-difference compact scheme (HOC). Both branches consistently show the occurrence of small-scale patterns at both vertical sidewalls in the Stewartson layers of the annulus. Small-scale flow structures are known to exist at the inner sidewall. In contrast, short-period waves at the outer sidewall have not yet been reported. The physical mechanisms that possibly trigger these patterns are discussed. We also debate whether these small-scale structures are a gravity wave signal.

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Stability of Quasi-Two-Dimensional Vortices

Cited by 5 publications

References 44 publications

A comparative study on instability of steady flows in helical pipes

A comparative study on instability of steady flows in helical pipes

Instabilities and small-scale waves within the Stewartson layers of a thermally driven rotating annulus

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