Laboratoire Matière et Systèmes Complexes

Laura Casanellas

Equipe DOMM

Exploring the onset of elastic flow instabilities in complex fluids : from microscopic-serpentine to macroscopic-Taylor-Couette flows

Viscoelastic fluids exhibit an intermediate behavior between elastic solids and dissipative liquids, depending on the time scale at which they are perturbed. Elastic instabilities occur at vanishing Reynolds number in the flow of viscoelastic fluids. The goal of my post-doctoral project is to study experimentally the onset of elastic flow instabilities in viscoelastic fluids of various rheologies and for different flow geometries, from microscopic to macroscopic ones.

Microfluidic devices bring the possibility to easily tune the flow curvature, as compared to more conventional macroscopic shearing geometries. Experiments realized in microfluidic serpentine channels show a strong dependence of the onset of elastic instabilities on the channel curvature, as well as on the fluid rheology. Alternatively, our macroscopic Taylor-Couette device enables to simultaneously measure the global and local stress response of the fluid. We succeed in identifying a transition from a laminar to

an elastically-driven turbulent flow regime, distinctive of various polymeric and wormlike micellar solutions. Furthermore, statistical analysis of the elastic fully-developed turbulence reveals anomalous scaling properties.

Iris Marangon

Equipe Biofluidique

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