Investigation of shear banding in three-dimensional foams
Résumé
We study the steady flow properties of different three-dimensional aqueous foams in a wide gap Couette geometry. From local velocity measurements through Magnetic Resonance Imaging techniques and from viscosity bifurcation experiments, we find that these foams do not exhibit any observable signature of shear banding. This contrasts with the results of two previous studies (Rodts et al., Europhys. Lett., 69 (2005) 636 and Da Cruz et al., Phys. Rev. E, 66 (2002) 051305); we discuss possible reasons for this dicrepancy. Our observations are not fitted by the model of Denkov et al., Phys. Rev. Lett., 103 (2009) 118302, which tends to overestimate the critical shear rate -- if any -- of the foams we studied. Local measurements of the constitutive law finally show that these foams behave as simple Herschel-Bulkley yield stress fluids.
Domaines
Matière Molle [cond-mat.soft]Origine | Fichiers produits par l'(les) auteur(s) |
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