Les paticules iso-denses forment-elles des amas ?

Autor: Fiabane, L., Volk, R., Pinton, J.F., Monchaux, R., Cartellier, A., Bourgoin, Mireille
Přispěvatelé: Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), École Nationale Supérieure de Techniques Avancées (ENSTA Paris), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), 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, Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: Physica Scripta
Physica Scripta, 2013, T155, pp.6. ⟨10.1088/0031-8949/2013/T155/014056⟩
Physica Scripta, IOP Publishing, 2013, T155, pp.6. ⟨10.1088/0031-8949/2013/T155/014056⟩
ISSN: 0031-8949
1402-4896
DOI: 10.1088/0031-8949/2013/T155/014056⟩
Popis: [Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]SPEE; International audience; The turbulent mixing of small and heavy particles presents a striking feature known as preferential concentration or clustering. We investigate here the preferential concentration of particles that are neutrally buoyant but with a diameter significantly larger than the dissipation scale η of the carrier flow (4.4η–17η). Such particles are known to not behave as flow tracers (Qureshi et al 2007 Phys. Rev. Lett. 99 184502) but it remains an open question whether they do cluster or not. For this purpose, we produce homogeneous and isotropic turbulence in a closed water flow, and seed the flow with neutrally buoyant particles spanning a range of Stokes numbers from 1.6 to 24.2 depending on the rotation frequency. The spatial structuration of these inclusions is then investigated by Voronoï tesselation analysis, as proposed recently by Monchaux et al (2010 Phys. Fluids 22 103304), from images of the particle concentration field taken in a laser sheet at the center of the flow. No matter what the rotation frequency and the Reynolds and Stokes numbers are, the particles are found to not cluster. Finite-size neutrally buoyant particles are therefore not inertial. We also conclude that the Stokes number per se is an insufficient indicator of the clustering trend in particles-laden flows.
Databáze: OpenAIRE
Externí odkaz: