Clustering of vector nulls in homogeneous isotropic turbulence

Autor: Pablo D. Mininni, Mickaël Bourgoin, Daniel Odens Mora, Martin Obligado
Přispěvatelé: Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Department of Mechanical Engineering [University of Washington], University of Washington [Seattle], Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure de Lyon (ENS de Lyon)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Departamento de Física [Universidad de Buenos Aires], Universidad de Buenos Aires [Buenos Aires] (UBA)-Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Physical Review Fluids
Physical Review Fluids, 2021, 6, ⟨10.1103/physrevfluids.6.024609⟩
Physical Review Fluids, American Physical Society, 2021, 6, ⟨10.1103/physrevfluids.6.024609⟩
ISSN: 2469-990X
Popis: International audience; We analyze the vector nulls of velocity, Lagrangian acceleration, and vorticity, coming from direct numerical simulations of forced homogeneous isotropic turbulence at Re λ ∈ O([40 − 600]). 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 Re λ and with characteristic turbulence lengthscales. We also analyze datasets of point inertial particles with Stokes numbers St = 0.5, 3, and 6, at Re λ = 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.
Databáze: OpenAIRE