title: Vesicle migration and spatial organization driven by flow line curvature.
abstract: Cross-streamline migration of deformable entities is essential in many problems such as industrial particulate flows, DNA sorting, and blood rheology. Using two-dimensional numerical experiments, we have discovered that vesicles suspended in a flow with curved flow lines migrate towards regions of high flowline curvature, which are regions of high shear rates. The migration velocity of a vesicle is found to be a universal function of the normal stress difference and the flow curvature. This finding quantitatively demonstrates a direct coupling between a microscopic quantity (migration) and a macroscopic one (normal stress difference). Furthermore, simulations with multiple vesicles revealed a self-organization, which corresponds to segregation, in a rim closer to the inner cylinder, resulting from a subtle interaction among vesicles. Such segregation effects could have a significant impact on the rheology of vesicle flows.
authors.affiliation: Université Joseph Fourier and CNRS (UMR5588), Laboratoire de Spectrométrie Physique, 140 Avenue de la Physique, 38402 Saint Martin d'Hères, France.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ghigliotti
authors.forename: Abtin
authors.initials: A
authors.lastname: Rahimian
authors.forename: George
authors.initials: G
authors.lastname: Biros
authors.forename: Chaouqi
authors.initials: C
authors.lastname: Misbah
mesh_terms: D000818:Animals; D003198:Computer Simulation; D003593:Cytoplasm / Q000737:chemistry*; D022162:Cytoplasmic Vesicles / Q000737:chemistry*; D006801:Humans; D044085:Microfluidics / Q000379:methods*; D008954:Models, Biological; D008956:Models, Chemical