On the velocity and dissipation signature of vortex tubes in isotropic turbulence

The properties of vortex tubes are extracted and analyzed from a DNS database at various ReλReλ, with the objective to characterize the associated distributions of induced velocity and kinetic energy dissipation. The induced velocity exhibits an inverse power-law scaling in the far field, different from Burgers’ r−1r−1 scaling, supporting the interpretation that tubes are the remnants of vortex sheets after roll-up, and suggesting a possible link with the Kolmogorov k−5/3k−5/3 spectral scaling. The energy dissipation signature is characterized by a local maximum near the edge of the vortex core, and an absolute peak at its center, which can be tentatively explained appealing to the occurrence of a bi-axial configuration of the strain-rate tensor.

► Vortex tubes exhibit an r−2/3r−2/3 scaling of induced velocity away from the core.
► The velocity scaling can be tentatively related to the formation of a k−5/3k−5/3 spectral range.
► The state of strain near vortex tubes is strongly bi-axial.
► Kinetic energy dissipation peaks at the center of vortex tubes, rather than in their periphery.