CALTAGIRONE, Jean-Paul

doi:10.3390/fluids8010016

CALTAGIRONE, Jean-Paul
Institut de Mécanique et d'Ingénierie [I2M]

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Ce document a été publié dans

Fluids. 2023-01-02, vol. 8, n° 1, p. 16

Résumé en anglais

The decay of the kinetic energy of a turbulent flow with time is not necessarily monotonic. This is revealed by simulations performed in the framework of discrete mechanics, where the kinetic energy can be transformed into pressure energy or vice versa; this persistent phenomenon is also observed for inviscid fluids. Different types of viscous vortex filaments generated by initial velocity conditions show that vortex stretching phenomena precede an abrupt onset of vortex bursting in highshear regions. In all cases, the kinetic energy starts to grow by borrowing energy from the pressure before the transfer phase to the small turbulent structures. The result observed on the vortex filament is also found for the Taylor–Green vortex, which significantly differs from the previous results on this same case simulated from the Navier–Stokes equations. This disagreement is attributed to the physical model used, that of discrete mechanics, where the formulation is based on the conservation of acceleration. The reasons for this divergence are analyzed in depth; however, a spectral analysis allows finding the established laws on the decay of kinetic energy as a function of the wave number.< Réduire

Mots clés en anglais

Turbulence cascade

Vortex stretching

Vortex bursting

Discrete mechanics

Conservation of acceleration

Helmholtz–Hodge decomposition

Inertial curvature

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https://oskar-bordeaux.fr/handle/20.500.12278/187903

DOI

http://dx.doi.org/10.3390/fluids8010016

Unités de recherche

Institut de Mécanique et d’Ingénierie de Bordeaux (I2M) - UMR 5295

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The Role of Inertia in the Onset of Turbulence in a Vortex Filament

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Résumé en anglais

Mots clés en anglais

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Unités de recherche