Bending oscillations of a cylinder freely falling in still fluid
| Autor: | Patricia Ern, Jérôme Mougel, Rémi Bourguet, Sébastien Cazin, M. Lorite-Díez |
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| Přispěvatelé: | Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Universidad de Jaén (UJA) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Buoyancy
Mécanique des fluides Bending Wake engineering.material 01 natural sciences Instability Bending oscillations 010305 fluids & plasmas Cylinder (engine) law.invention Physics::Fluid Dynamics symbols.namesake law 0103 physical sciences [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] 010306 general physics Physics Wakes Mechanical Engineering Reynolds number Mechanics Flow–structure interactions Condensed Matter Physics Vortex shedding Mechanics of Materials symbols engineering Deformation (engineering) still fluid |
| Zdroj: | Journal of Fluid Mechanics Journal of Fluid Mechanics, Cambridge University Press (CUP), 2020, 905, ⟨10.1017/jfm.2020.828⟩ |
| ISSN: | 0022-1120 1469-7645 |
| DOI: | 10.1017/jfm.2020.828⟩ |
| Popis: | International audience; We investigate experimentally the behavior of an elongated flexible cylinder settling at moderate Reynolds number under the effect of buoyancy in a fluid otherwise at rest. The experiments uncover the development of large-amplitude periodic deformations of the cylinder (of the order of its diameter) in specific parameter ranges. Bending oscillations are observed to occur for two base flow situations, involving either a steady or an unsteady wake. In both cases, the sequence of oscillatory deformations emerging when the cylinder length is increased involves the bending modes of an unsupported cylinder with free ends. Comparison of the deformation frequency measured for the falling cylinder with the vortex shedding frequency expected for a non-deformable cylinder at the same Reynolds number indicates that the deformation is coupled to the wake unsteadiness. It also suggests that the cylinder degrees of freedom in deformability allow wake instability to be triggered at Reynolds numbers that would be subcritical for fixed rigid cylinders. |
| Databáze: | OpenAIRE |
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