Unsteady drag force on an immersed sphere oscillating near a wall - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Fluid Mechanics Année : 2023

Unsteady drag force on an immersed sphere oscillating near a wall

Résumé

The unsteady hydrodynamic drag exerted on an oscillating sphere near a planar wall is addressed experimentally, theoretically, and numerically. The experiments are performed by using colloidal-probe Atomic Force Microscopy (AFM) in thermal noise mode. The natural resonance frequencies and quality factors are extracted from the measurement of the power spectrum density of the probe oscillation for a broad range of gap distances and Womersley numbers. The shift in the natural resonance frequency of the colloidal probe as the probe goes close to a solid wall infers the wall-induced variations of the effective mass of the probe. Interestingly, a crossover from a positive to a negative shift is observed as the Womersley number increases. In order to rationalize the results, the confined unsteady Stokes equation is solved numerically using a finite-element method, as well as asymptotic calculations. The in-phase and out-of-phase terms of the hydrodynamic drag acting on the sphere are obtained and agree well to the experimental results. All together, the experimental, theoretical, and numerical results show that the hydrodynamic force felt by an immersed sphere oscillating near a wall is highly dependent on the Womersley number.
Fichier principal
Vignette du fichier
Main.pdf (1.41 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-04158163 , version 1 (10-07-2023)

Identifiants

Citer

Zaicheng Zhang, Vincent Bertin, Martin Essink, Hao Zhang, Nicolas Fares, et al.. Unsteady drag force on an immersed sphere oscillating near a wall. Journal of Fluid Mechanics, 2023, 977, pp.A21. ⟨hal-04158163⟩

Collections

CNRS LOMA ANR
27 Consultations
8 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More