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Accueil > Publications > Archives 2004-2010 > 2007

Evidence for three-dimensional unstable flows in shear-banding wormlike micelles

L. Bécu, D. Anache, S. Manneville, and A. Colin — Phys. Rev. E 76, 011503 (2007)

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We report on an experimental study of the shear-banding phenomenon in the concentrated wormlike micellar
system CTAB at 20 wt. % in D2O. Time-resolved velocity profiles are recorded using ultrasonic velocimetry
simultaneously to global rheological data. Our results confirm the studies performed previously by Fischer and
Callaghan [Phys. Rev. E 64, 011501 -(2001)]. Time averaged velocity profiles display an unsheared ?nematic gel ?. In the range of applied shear rate, the flow field exhibits very fast temporal fluctuations. Suspicions for the
presence of three-dimensional flow are evidenced and possible causes for a three-dimensional instability are
discussed together with the coupling of wall slip to bulk dynamic.