Naissance des corrélations triples de vorticité dans une turbulence statistiquement homogène soumise à une rotation

Gence, J. N.; Frick, Christine

doi:10.1016/s1620-7742(01)01338-1

Cited by 18 publications

(21 citation statements)

References 2 publications

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“…This second structure (best seen in figure 12(b)) is fluctuating strongly having more small scales. The persistence of corotating structures in rotating turbulence has been observed in experiments (Hopfinger et al 1982;Morize et al 2005;Gallet et al 2014) and has been discussed in various works (Hopfinger & van Heijst 1993;Bartello et al 1994;Gence & Frick 2001;Sreenivasan & Davidson 2008;Staplehurst et al 2008;Gallet et al 2014). Perhaps it is not surprising that structures with vorticity anti-aligned to rotation are more responsive to 3D perturbations.…”

Section: Intermittent Burstsmentioning

confidence: 86%

Rotating Taylor–Green flow

Alexakis

2015

J. Fluid Mech.

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The steady state of a forced Taylor-Green flow is investigated in a rotating frame of reference. The investigation involves the results of 184 numerical simulations for different Reynolds numbers Re F and Rossby numbers Ro F . The large number of examined runs allows a systematic study that enables the mapping of the different behaviours observed to the parameter space (Re F , Ro F ), and the examination of different limiting procedures for approaching the large Re F small Ro F limit. Four distinctly different states were identified: laminar, intermittent bursts, quasi-twodimensional condensates and weakly rotating turbulence. These four different states are separated by power-law boundaries Ro F ∝ Re −γ F in the small Ro F limit. In this limit, the predictions of asymptotic expansions can be directly compared with the results of the direct numerical simulations. While the first-order expansion is in good agreement with the results of the linear stability theory, it fails to reproduce the dynamical behaviour of the quasi-two-dimensional part of the flow in the nonlinear regime, indicating that higher-order terms in the expansion need to be taken into account. The large number of simulations allows also to investigate the scaling that relates the amplitude of the fluctuations with the energy dissipation rate and the control parameters of the system for the different states of the flow. Different scaling was observed for different states of the flow, that are discussed in detail. The present results clearly demonstrate that the limits of small Rossby and large Reynolds numbers do not commute and it is important to specify the order in which they are taken.

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Section: Intermittent Burstsmentioning

confidence: 86%

Rotating Taylor–Green flow

Alexakis

2015

J. Fluid Mech.

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“…There are, however, other possible explanations for the asymmetry. For example, Gence & Frick (2001) considered fully developed, isotropic turbulence which is suddenly subjected Figure 18. Probability density function of the axial vorticity, ω z : -, initial distribution;…”

Section: Statistics In a Horizontal Planementioning

confidence: 99%

Structure formation in homogeneous freely decaying rotating turbulence

2008

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One of the most striking features of rotating turbulence is the inevitable appearance of large-scale columnar structures. Whilst these structures are frequently observed, the processes by which they are created are still poorly understood. In this paper we consider the emergence of these structures from freely decaying, rotating turbulence with Ro ∼ 1. Our study follows the conjecture by Davidson, Staplehurst & Dalziel (J. Fluid Mech., vol. 557, 2006, p. 135) that the structure formation may be due to linear inertial wave propagation, which was shown to be consistent with the growth of columnar eddies in inhomogeneous turbulence. Here we extend that work and consider the case of homogeneous turbulence.We describe laboratory experiments where homogeneous turbulence is created in a rotating tank. The turbulence is generated with Ro ∼ 1, and as the energy decays, the formation of columnar vortices is observed. The axial growth of these columnar structures is then measured using two-point correlations and in all cases the results are consistent with structure formation via linear inertial wave propagation. In particular, we obtain a self-similar collapse of the two-point correlations when the axial coordinate is normalized by Ωtb, where b is a measure of the integral scale in the horizontal plane and Ω is the rotation rate. Although our results do not exclude the possibility of significant nonlinear dynamics, they are consistent with the conjecture of Davidson et al. (2006) that linear dynamics play a strong guiding hand in structure formation. IntroductionWe consider rapidly rotating turbulence in which the fluctuating velocity, u, is small in comparison with |Ω|l, where Ω = Ωê z is the bulk rotation rate and l the integral scale of the turbulence. It is well known that such turbulence is characterized by the growth of columnar eddies aligned with the rotation axis (Hopfinger, Browand & Gagne 1982) and there has been considerable debate as to the physical mechanisms responsible for this anisotropy.Most researchers agree that inertial waves play a crucial role in the formation of these columnar vortices, which makes them quite different to, say, the coherent vortices seen in two-dimensional turbulence. Indeed, when inertia is weak by comparison with the Coriolis force, u · ∇u 2u × Ω, the motion is simply a linear superposition of inertial waves. Many theories have emerged, but typically they focus on the case of small Rossby number, Ro = u/2Ωl 1, and suggest that anisotropy results from a weak nonlinear coupling of inertial waves operating over a long period of time,

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“…In particular, it has been shown that the cyclones and anticyclones have different stability properties [31] and different probabilities to be generated at finite Rossby number [33]. Moreover, the correlations between the strain tensor and the vorticity in isotropic turbulence can be responsible for the development of a positive skewness of vertical vorticity when the flow is suddenly subjected to rotation [34]. Interestingly, a similar asymmetry has been observed also in the tropopause [35] and in the stratosphere [36], even though the physical mechanisms acting in the atmosphere are more complex than in idealized rotating turbulence.…”

Section: Introductionmentioning

confidence: 99%

Dimensional transition in rotating turbulence

et al. 2014

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In this work we investigate, by means of direct numerical hyperviscous simulations, how rotation affects the bidimensionalization of a turbulent flow. We study a thin layer of fluid, forced by a two-dimensional forcing, within the framework of the "split cascade" in which the injected energy flows both to small scales (generating the direct cascade) and to large scale (to form the inverse cascade). It is shown that rotation reinforces the inverse cascade at the expense of the direct one, thus promoting bidimensionalization of the flow. This is achieved by a suppression of the enstrophy production at large scales. Nonetheless, we find that, in the range of rotation rates investigated, increasing the vertical size of the computational domain causes a reduction of the flux of the inverse cascade. Our results suggest that, even in rotating flows, the inverse cascade may eventually disappear when the vertical scale is sufficiently large with respect to the forcing scale. We also study how the split cascade and confinement influence the breaking of symmetry induced by rotation.

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Naissance des corrélations triples de vorticité dans une turbulence statistiquement homogène soumise à une rotation

Cited by 18 publications

References 2 publications

Rotating Taylor–Green flow

Rotating Taylor–Green flow

Structure formation in homogeneous freely decaying rotating turbulence

Dimensional transition in rotating turbulence

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