Interaction entre écoulement de Stokes et micro-objets (thèse 2016 - 2019)
Publications scientifiques au M2P2
Paul G. Chen, J Lyu, M Jaeger, M. Leonetti. Shape transition and hydrodynamics of vesicles in tube flow. Physical Review Fluids, American Physical Society, 2020, 5 (4), pp.043602. ⟨10.1103/PhysRevFluids.5.043602⟩. ⟨hal-02415320v2⟩ Plus de détails...
The steady motion and deformation of a lipid-bilayer vesicle translating through a circular tube in low Reynolds number pressure-driven flow are investigated numerically using an axisymmetric boundary element method. This fluid-structure interaction problem is determined by three dimen-sionless parameters: reduced volume (a measure of the vesicle asphericity), geometric confinement (the ratio of the vesicle effective radius to the tube radius), and capillary number (the ratio of viscous to bending forces). The physical constraints of a vesicle--fixed surface area and enclosed volume when it is confined in a tube--determine critical confinement beyond which it cannot pass through without rupturing its membrane. The simulated results are presented in a wide range of reduced volumes [0.6, 0.98] for different degrees of confinement; the reduced volume of 0.6 mimics red blood cells. We draw a phase diagram of vesicle shapes and propose a shape transition line separating the parachutelike shape region from the bulletlike one in the reduced volume versus confinement phase space. We show that the shape transition marks a change in the behavior of vesicle mobility, especially for highly deflated vesicles. Most importantly, high-resolution simulations make it possible for us to examine the hydrodynamic interaction between the wall boundary and the vesicle surface at conditions of very high confinement, thus providing the limiting behavior of several quantities of interest, such as the thickness of lubrication film, vesicle mobility and its length, and the extra pressure drop due to the presence of the vesicle. This extra pressure drop holds implications for the rheology of dilute vesicle suspensions. Furthermore, we present various correlations and discuss a number of practical applications. The results of this work may serve as a benchmark for future studies and help devise tube-flow experiments.
Paul G. Chen, J Lyu, M Jaeger, M. Leonetti. Shape transition and hydrodynamics of vesicles in tube flow. Physical Review Fluids, American Physical Society, 2020, 5 (4), pp.043602. ⟨10.1103/PhysRevFluids.5.043602⟩. ⟨hal-02415320v2⟩
Jinming Lyu, Paul G. Chen, Gwenn Boedec, Marc Leonetti, Marc Jaeger. Hybrid continuum–coarse-grained modeling of erythrocytes. Comptes Rendus Mécanique, Elsevier Masson, 2018, 346, pp.439-448. ⟨10.1016/j.crme.2018.04.015⟩. ⟨hal-01785429⟩ Plus de détails...
The red blood cell (RBC) membrane is a composite structure, consisting of a phospholipid bilayer and an underlying membrane-associated cytoskeleton. Both continuum and particle-based coarse-grained RBC models make use of a set of vertices connected by edges to represent the RBC membrane, which can be seen as a triangular surface mesh for the former and a spring network for the latter. Here, we present a modeling approach combining an existing continuum vesicle model with a coarse-grained model for the cytoskeleton. Compared to other two-component approaches, our method relies on only one mesh, representing the cytoskeleton, whose velocity in the tangential direction of the membrane may be different from that of the lipid bilayer. The finitely extensible nonlinear elastic (FENE) spring force law in combination with a repulsive force defined as a power function (POW), called FENE-POW, is used to describe the elastic properties of the RBC membrane. The mechanical interaction between the lipid bilayer and the cytoskeleton is explicitly computed and incorporated into the vesicle model. Our model includes the fundamental mechanical properties of the RBC membrane, namely fluidity and bending rigidity of the lipid bilayer, and shear elasticity of the cytoskeleton while maintaining surface-area and volume conservation constraint. We present three simulation examples to demonstrate the effectiveness of this hybrid continuum--coarse-grained model for the study of RBCs in fluid flows.
Jinming Lyu, Paul G. Chen, Gwenn Boedec, Marc Leonetti, Marc Jaeger. Hybrid continuum–coarse-grained modeling of erythrocytes. Comptes Rendus Mécanique, Elsevier Masson, 2018, 346, pp.439-448. ⟨10.1016/j.crme.2018.04.015⟩. ⟨hal-01785429⟩