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Flow instabilities in giant micelles : from shear-banding to elastic turbulence
In the past twenty years, shear-banding flows have been probed by various techniques, such as rheometry, velocimetry and flow
birefringence. In micellar solutions, many of the data collected
exhibit unexplained spatio-temporal fluctuations. Recently, it has
been suggested that those fluctuations originate from a purely elastic instability of the flow. In cylindrical Couette geometry, the
instability is reminiscent of the Taylor-like instability observed in
viscoelastic polymer solutions. In this talk, we will describe how the
criterion for purely elastic Taylor-Couette instability should be
adapted to shear-banding flows. We will derive three categories of
shear-banding flows with curved streamlines, depending on their
stability. Those three categories will be illustrated through
different examples of micellar solutions.
Séminaires Gulliver : consulter le programme