TY - JOUR

T1 - Hydrodynamics and rheology of a vesicle doublet suspension

AU - Quaife, Bryan

AU - Veerapaneni, Shravan

AU - Young, Y. N.

N1 - Funding Information:
B.Q. acknowledges support from Florida State University startup funds and Simons Foundation Mathematics and Physical Sciences-Collaboration Grants for Mathematicians 527139. S.V. acknowledges support from NSF-DMS 1719834 and NSF-DMS 1454010. Y.N.Y. acknowledges support from NSF-DMS 1614863 and NSF-DMS 1412789. Both S.V. and Y.N.Y. were also supported by the Flatiron Institute, a division of Simons Foundation. B.Q. and Y.N.Y. contributed equally to model development and simulations. B.Q. developed the code. All authors contributed equally to writing the manuscript. APPENDIX A:

PY - 2019/10/10

Y1 - 2019/10/10

N2 - The dynamics of an adhesive two-dimensional vesicle doublet under various flow conditions is investigated numerically using a high-order, adaptive-in-time boundary integral method. In a quiescent flow, two nearby vesicles move slowly toward each other under the adhesive potential, pushing out fluid between them to form a vesicle doublet at equilibrium. A lubrication analysis on such draining of a thin film gives the dependencies of draining time on adhesion strength and separation distance, which are in good agreement with numerical results. In a planar extensional flow, we find that a stable vesicle doublet forms only when two vesicles collide head-on around the stagnation point. In a microfluid trap where the stagnation of an extensional flow is dynamically placed in the middle of a vesicle doublet through an active control loop, novel dynamics of a vesicle doublet are observed. Numerical simulations show that there exists a critical extensional flow rate above which adhesive interaction is overcome by the diverging stream, thus providing a simple method to measure the adhesion strength between two vesicle membranes. In a planar shear flow, numerical simulations reveal that a vesicle doublet may form provided that the adhesion strength is sufficiently large at a given vesicle reduced area. Once a doublet is formed, its oscillatory dynamics is found to depend on the adhesion strength and their reduced area. Furthermore the effective shear viscosity of a dilute suspension of vesicle doublets is found to be a function of the reduced area. Results from these numerical studies and analysis shed light on the hydrodynamic and rheological consequences of adhesive interactions between vesicles in a viscous fluid.

AB - The dynamics of an adhesive two-dimensional vesicle doublet under various flow conditions is investigated numerically using a high-order, adaptive-in-time boundary integral method. In a quiescent flow, two nearby vesicles move slowly toward each other under the adhesive potential, pushing out fluid between them to form a vesicle doublet at equilibrium. A lubrication analysis on such draining of a thin film gives the dependencies of draining time on adhesion strength and separation distance, which are in good agreement with numerical results. In a planar extensional flow, we find that a stable vesicle doublet forms only when two vesicles collide head-on around the stagnation point. In a microfluid trap where the stagnation of an extensional flow is dynamically placed in the middle of a vesicle doublet through an active control loop, novel dynamics of a vesicle doublet are observed. Numerical simulations show that there exists a critical extensional flow rate above which adhesive interaction is overcome by the diverging stream, thus providing a simple method to measure the adhesion strength between two vesicle membranes. In a planar shear flow, numerical simulations reveal that a vesicle doublet may form provided that the adhesion strength is sufficiently large at a given vesicle reduced area. Once a doublet is formed, its oscillatory dynamics is found to depend on the adhesion strength and their reduced area. Furthermore the effective shear viscosity of a dilute suspension of vesicle doublets is found to be a function of the reduced area. Results from these numerical studies and analysis shed light on the hydrodynamic and rheological consequences of adhesive interactions between vesicles in a viscous fluid.

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U2 - 10.1103/PhysRevFluids.4.103601

DO - 10.1103/PhysRevFluids.4.103601

M3 - Article

AN - SCOPUS:85074477455

VL - 4

JO - Physical Review Fluids

JF - Physical Review Fluids

SN - 2469-990X

IS - 10

M1 - 103601

ER -