We study small-scale and high-frequency turbulent fluctuations in three- dimensional flows under Fourier-mode reduction. The Navier-Stokes equations are evolved on a restricted set of modes, obtained as a projection on a fractal or homogeneous Fourier set. We find a strong sensitivity (reduction) of the high-frequency variability of the Lagrangian velocity fluctuations on the degree of mode decimation, similarly to what is already reported for Eulerian statistics. This is quantified by a tendency towards a quasi-Gaussian statistics, i.e., to a reduction of intermittency, at all scales and frequencies. This can be attributed to a strong depletion of vortex filaments and of the vortex stretching mechanism. Nevertheless, we found that Eulerian and Lagrangian ensembles are still connected by a dimensional bridge-relation which is independent of the degree of Fourier-mode decimation.

Buzzicotti, M., Bhatnagar, A., Biferale, L., Lanotte, A., & Ray, S. (2016). Lagrangian statistics for Navier-Stokes turbulence under Fourier-mode reduction: Fractal and homogeneous decimations. NEW JOURNAL OF PHYSICS, 18(11), 113047 [10.1088/1367-2630/18/11/113047].

Lagrangian statistics for Navier-Stokes turbulence under Fourier-mode reduction: Fractal and homogeneous decimations

BUZZICOTTI, MICHELE;BIFERALE, LUCA;
2016

Abstract

We study small-scale and high-frequency turbulent fluctuations in three- dimensional flows under Fourier-mode reduction. The Navier-Stokes equations are evolved on a restricted set of modes, obtained as a projection on a fractal or homogeneous Fourier set. We find a strong sensitivity (reduction) of the high-frequency variability of the Lagrangian velocity fluctuations on the degree of mode decimation, similarly to what is already reported for Eulerian statistics. This is quantified by a tendency towards a quasi-Gaussian statistics, i.e., to a reduction of intermittency, at all scales and frequencies. This can be attributed to a strong depletion of vortex filaments and of the vortex stretching mechanism. Nevertheless, we found that Eulerian and Lagrangian ensembles are still connected by a dimensional bridge-relation which is independent of the degree of Fourier-mode decimation.
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
English
Con Impact Factor ISI
Buzzicotti, M., Bhatnagar, A., Biferale, L., Lanotte, A., & Ray, S. (2016). Lagrangian statistics for Navier-Stokes turbulence under Fourier-mode reduction: Fractal and homogeneous decimations. NEW JOURNAL OF PHYSICS, 18(11), 113047 [10.1088/1367-2630/18/11/113047].
Buzzicotti, M; Bhatnagar, A; Biferale, L; Lanotte, A; Ray, S
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/173926
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