学術雑誌論文

学術雑誌論文

Physical Review Fluids. 2021, 6(4), p. 044605

Generalized sweep-stick mechanism of inertial-particle clustering in turbulence

American Physical Society

英語

2021-04-08

https://doi.org/10.1103/PhysRevFluids.6.044605

Oka S., Goto S. Generalized sweep-stick mechanism of inertial-particle clustering in turbulence. Physical Review Fluids 6, 044605 (2021); https://doi.org/10.1103/PhysRevFluids.6.044605.

Inertial particles, i.e., small heavy particles, can inhomogeneously distribute and form clusters even in statistically homogeneous turbulence. When the Reynolds number of turbulence is sufficiently high so that coherent structures with various length and time scales coexist, particles form clusters by the action of the coherent structures when the particle velocity relaxation time is in the inertial-range time scales. In general, thus formed clusters are larger for larger Stokes numbers (the nondimensional relaxation time). We propose a method to objectively describe the particle cluster created by the action of coherent structures in the inertial range. For this purpose, we generalize the sweep-stick mechanism [S. Goto and J. C. Vassilicos, Phys. Rev. Lett. 100, 054503 (2008)] to express two-dimensional sheetlike clusters in terms of the coarse-grained acceleration field of turbulence. The generalized mechanism also predicts the thickness of the clusters, which depends on the particle relaxation time, the magnitude of acceleration gradients, and the lifetime of coherent flow structures. The direct numerical simulations of fully developed turbulence in a periodic cube with the Taylor-length Reynolds number being about 740 support the proposed mechanism.

Copyright 2021 by the American Physical Society

100042

Generalized sweep-stick mechanism of inertial-particle clustering in turbulence

American Physical Society

英語

2021-04-08

Physical Review Fluids

6

4

044605

https://doi.org/10.1103/PhysRevFluids.6.044605

https://hdl.handle.net/11094/100042