Clustering of vector nulls in homogeneous isotropic turbulence

D. O. Mora, M. Bourgoin, P. D. Mininni, and M. Obligado
Phys. Rev. Fluids 6, 024609 – Published 26 February 2021

Abstract

We analyze the vector nulls of velocity, Lagrangian acceleration, and vorticity, coming from direct numerical simulations of forced homogeneous isotropic turbulence at ReλO([40600]). We show that the clustering of velocity nulls is much stronger than those of acceleration and vorticity nulls. These acceleration and vorticity nulls, however, are denser than the velocity nulls. We study the scaling of clusters of these null points with Reλ and with characteristic turbulence lengthscales. We also analyze datasets of point inertial particles with Stokes numbers St=0.5, 3, and 6, at Reλ=240. Inertial particles display preferential concentration with a degree of clustering that resembles some properties of the clustering of the Lagrangian acceleration nulls, in agreement with the proposed sweep-stick mechanism of clustering formation.

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  • Received 28 July 2020
  • Accepted 11 February 2021

DOI:https://doi.org/10.1103/PhysRevFluids.6.024609

©2021 American Physical Society

Physics Subject Headings (PhySH)

Fluid Dynamics

Authors & Affiliations

D. O. Mora1,2, M. Bourgoin3, P. D. Mininni4, and M. Obligado1

  • 1Université Grenoble Alpes, CNRS, Grenoble-INP, LEGI, F-38000 Grenoble, France
  • 2Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195-2600, USA
  • 3Univ Lyon, Ens de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique, 46 allée d'Italie, F-69342 Lyon, France
  • 4Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Física, & IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428, Argentina

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Vol. 6, Iss. 2 — February 2021

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