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Three-dimensional analysis of precursors to non-viscous dissipation in an experimental turbulent flow
- Source :
- Journal of Fluid Mechanics, Journal of Fluid Mechanics, 2021, 914, pp.A9. ⟨10.1017/jfm.2020.574⟩, Journal of Fluid Mechanics, Cambridge University Press (CUP), 2021, 914, ⟨10.1017/jfm.2020.574⟩
- Publication Year :
- 2021
- Publisher :
- Cambridge University Press (CUP), 2021.
-
Abstract
- International audience; We study the three-dimensional structure of turbulent velocity fields around extreme events of local energy transfer in the dissipative range. Velocity fields are measured by tomographic particle velocimetry at the centre of a von Kármán flow with resolution reaching the Kolmogorov scale. The characterization is performed through both direct observation and an analysis of the velocity gradient tensor invariants at the extremes. The conditional average of local energy transfer on the second and third invariants seems to be the largest in the sheet zone, but the most extreme events of local energy transfer mostly correspond to the vortex stretching topology. The direct observation of the velocity fields allows for identification of three different structures: the screw and roll vortices, and the U-turn. They may correspond to a single structure seen at different times or in different frames of reference. The extreme events of local energy transfer come along with large velocity and vorticity norms, and the structure of the vorticity field around these events agrees with previous observations of numerical works at similar Reynolds numbers.
- Subjects :
- Physics
Field (physics)
Turbulence
Mechanical Engineering
010102 general mathematics
Kolmogorov microscales
Reynolds number
[PHYS.MECA]Physics [physics]/Mechanics [physics]
Mechanics
Vorticity
Condensed Matter Physics
01 natural sciences
010305 fluids & plasmas
Vortex
Physics::Fluid Dynamics
symbols.namesake
Mechanics of Materials
Vortex stretching
0103 physical sciences
symbols
Dissipative system
0101 mathematics
Subjects
Details
- ISSN :
- 14697645 and 00221120
- Volume :
- 914
- Database :
- OpenAIRE
- Journal :
- Journal of Fluid Mechanics
- Accession number :
- edsair.doi.dedup.....940878ffee2f122f28e08d0aefdaea58