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DY: Fachverband Dynamik und Statistische Physik
DY 70: Poster: Flows, Patterns, Delay, Reaction Diffusion
DY 70.14: Poster
Donnerstag, 15. März 2018, 15:30–18:00, Poster A
Does a vesicle migrate to the center or to the periphery in a bounded shear flow? — •Abdessamad Nait Ouhra1,2, Alexander Farutin1, Hamid Ez-Zahraouy2, Abdelilah Benyoussef3, and Chaouqi Misbah1 — 1Grenoble Alpes University, CNRS, LIPhy, Grenoble, France — 2Mohammed V University, Rabat, Morocco — 3Hassan II Academy of Science and Technology, Rabat, Morocco
The lateral migration of a suspended vesicle (a model of red blood cells (RBCs)) in a bounded shear flow is investigated numerically at vanishing Reynolds number (the Stokes limit) using a boundary integral method. We explore the relevant dimensionless parameters to study the dynamics and rheology of a vesicle as a function of the viscosity contrast λ=ηin/ηout, where ηin, ηout denote the inner and the outer viscosities. A vesicle is found to migrate to the centerline or to the wall depending on λ. We found that below a critical viscosity contrast λc, the vesicle is centered, and above λc, the vesicle can be either centered or off-center depending on initial condition. The equilibrium lateral position of the vesicle exhibits a saddle-node bifurcation as a function of the bifurcation parameter λ, which leads to a surprising acute decrease of the effective viscosity of the suspension at a critical value of viscosity contrast (λc). This study can be exploited in the problem of cell sorting out and can help understanding the intricate nature of the rheology of confined suspensions.