学術雑誌論文

学術雑誌論文

Physical Review Fluids. 2017, 2(6), p. 064603

Hierarchy of antiparallel vortex tubes in spatially periodic turbulence at high Reynolds numbers

American Physical Society

英語

2017-06-06

https://doi.org/10.1103/PhysRevFluids.2.064603

Goto S., Saito Y., Kawahara G. Hierarchy of antiparallel vortex tubes in spatially periodic turbulence at high Reynolds numbers. Physical Review Fluids 2, 064603 (2017); https://doi.org/10.1103/PhysRevFluids.2.064603.

To draw a precise picture of the hierarchy of coherent vortices in spatially periodic turbulence at high Reynolds numbers and to understand its generation mechanism, we conduct direct numerical simulations of turbulence in a periodic cube. By objectively identifying the axes of vortex tubes at various length scales in the inertial range, we quantitatively show that the sustained turbulence consists of a hierarchy of antiparallel pairs of vortex tubes. These vortex tubes are created by being stretched in strain fields around 2-8 times larger vortices, whereas they are weakened by strain around half-scale vortices. Temporal tracking of identified vortex tubes shows that they tend to form antiparallel pairs from the moment they are created. We examine three different external forces to show that the hierarchical structure of antiparallel vortex pairs is robust and its statistical features in inertial length scales are independent of the force. The turbulence that is sustained by steady forces is quasiperiodic in time and its significant temporal fluctuations are caused by successive creation of strong vortex tubes within the hierarchy.

Copyright 2017 by the American Physical Society

100049

Hierarchy of antiparallel vortex tubes in spatially periodic turbulence at high Reynolds numbers

American Physical Society

英語

2017-06-06

Physical Review Fluids

2

6

064603

https://doi.org/10.1103/PhysRevFluids.2.064603

https://hdl.handle.net/11094/100049