Acceleration and vortex filaments in turbulence

Toschi, Federico; Biferale, Luca; Boffetta, G.; Celani, Antonio; Devenish, B. J.; Lanotte, Alessandra S.

doi:10.1080/14685240500103150

Cited by 31 publications

(23 citation statements)

References 28 publications

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“…It has long been known that acceleration of tracers is very intermittent [49]. Tracers may be trapped by a strong vortex filament and experience strong acceleration [50,51]. For compressible flow, shocklets become a new source of strong acceleration because of the extremely large pressure gradient near shocklet surfaces.…”

Section: Preliminary Results Of Lagrangian Studymentioning

confidence: 99%

Recent progress in compressible turbulence

et al. 2015

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In this paper, we review some recent studies on compressible turbulence conducted by the authors' group, which include fundamental studies on compressible isotropic turbulence (CIT) and applied studies on developing a constrained large eddy simulation (CLES) for wall-bounded turbulence. In the first part, we begin with a newly proposed hybrid compact-weighted essentially nonoscillatory (WENO) scheme for a CIT simulation that has been used to construct a systematic database of CIT. Using this database various fundamental properties of compressible turbulence have been examined, including the statistics and scaling of compressible modes, the shocklet-turbulence interaction, the effect of local compressibility on small scales, the kinetic energy cascade, and some preliminary results from a Lagrangian point of view. In the second part, the idea and formulas of the CLES are reviewed, followed by the validations of CLES and some applications in compressible engineering problems.

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Section: Preliminary Results Of Lagrangian Studymentioning

confidence: 99%

Recent progress in compressible turbulence

et al. 2015

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“…This has been observed for the Lagrangian turbulence, in which the high intensity event is known as "vortex trapping" process. 42,45 …”

Section: B Fourier Power Spectrum and Second-order Structure-functionmentioning

confidence: 99%

Hilbert statistics of vorticity scaling in two-dimensional turbulence

Tan¹,

Huang²,

Meng³

2014

Physics of Fluids

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In this paper, the scaling property of the inverse energy cascade and forward enstrophy cascade of the vorticity filed ω(x, y) in two-dimensional (2D) turbulence is analyzed. This is accomplished by applying a Hilbert-based technique, namely Hilbert-Huang transform, to a vorticity field obtained from a 81922 grid-points direct numerical simulation of the 2D turbulence with a forcing scale kf = 100 and an Ekman friction. The measured joint probability density function p(C, k) of mode Ci(x) of the vorticity ω and instantaneous wavenumber k(x) is separated by the forcing scale kf into two parts, which correspond to the inverse energy cascade and the forward enstrophy cascade. It is found that all conditional probability density function p(C|k) at given wavenumber k has an exponential tail. In the inverse energy cascade, the shape of p(C|k) does collapse with each other, indicating a nonintermittent cascade. The measured scaling exponent \documentclass[12pt]{minimal}\begin{document}$\zeta _{\omega }^I(q)$\end{document}ζωI(q) is linear with the statistical order q, i.e., \documentclass[12pt]{minimal}\begin{document}$\zeta _{\omega }^I(q)=-q/3$\end{document}ζωI(q)=−q/3, confirming the nonintermittent cascade process. In the forward enstrophy cascade, the core part of p(C|k) is changing with wavenumber k, indicating an intermittent forward cascade. The measured scaling exponent \documentclass[12pt]{minimal}\begin{document}$\zeta _{\omega }^F(q)$\end{document}ζωF(q) is nonlinear with q and can be described very well by a log-Poisson fitting: \documentclass[12pt]{minimal}\begin{document}$\zeta _{\omega }^F(q)=\frac{1}{3}q+0.45\left( 1-0.43^{q}\right)$\end{document}ζωF(q)=13q+0.451−0.43q. However, the extracted vorticity scaling exponents ζω(q) for both inverse energy cascade and forward enstrophy cascade are not consistent with Kraichnan's theory prediction. New theory for the vorticity field in 2D turbulence is required to interpret the observed scaling behavior.

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“…On the one hand, it has been successfully used to predict the probability density function of accelerations and the relative scaling between Lagrangian structure functions [8][9][10][11]. On the other hand, when looking at direct scaling versus the time lag, inconclusive results have been obtained [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

A new assessment of the second-order moment of Lagrangian velocity increments in turbulence

Lanotte

Biferale

Boffetta

et al. 2013

Journal of Turbulence

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The behavior of the second-order Lagrangian structure functions on state-of-the-art numerical data both in two and three dimensions is studied. On the basis of a phenomenological connection between Eulerian space-fluctuations and the Lagrangian time-fluctuations, it is possible to rephrase the Kolmogorov 4/5-law into a relation predicting the linear (in time) scaling for the second order Lagrangian structure function. When such a function is directly observed on current experimental or numerical data, it does not clearly display a scaling regime. A parameterization of the Lagrangian structure functions based on Batchelor model is introduced and tested on data for 3d turbulence, and for 2d turbulence in the inverse cascade regime. Such parameterization supports the idea, previously suggested, that both Eulerian and Lagrangian data are consistent with a linear scaling plus finite-Reynolds number effects affecting the small-and large-time scales. When largetime saturation effects are properly accounted for, compensated plots show a detectable plateau already at the available Reynolds number. Furthermore, this parameterization allows us to make quantitative predictions on the Reynolds number value for which Lagrangian structure functions are expected to display a scaling region. Finally, we show that this is also sufficient to predict the anomalous dependency of the normalized root mean squared acceleration as a function of the Reynolds number, without fitting parameters.2

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Acceleration and vortex filaments in turbulence

Cited by 31 publications

References 28 publications

Recent progress in compressible turbulence

Recent progress in compressible turbulence

Hilbert statistics of vorticity scaling in two-dimensional turbulence

A new assessment of the second-order moment of Lagrangian velocity increments in turbulence

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