25 research outputs found
Dynamics of Fluid Vesicles in Oscillatory Shear Flow
The dynamics of fluid vesicles in oscillatory shear flow was studied using
differential equations of two variables: the Taylor deformation parameter and
inclination angle . In a steady shear flow with a low viscosity
of internal fluid, the vesicles exhibit steady tank-treading
motion with a constant inclination angle . In the oscillatory flow
with a low shear frequency, oscillates between or
around for zero or finite mean shear rate ,
respectively. As shear frequency increases, the vesicle
oscillation becomes delayed with respect to the shear oscillation, and the
oscillation amplitude decreases. At high with , another limit-cycle oscillation between and
is found to appear. In the steady flow, periodically rotates
(tumbling) at high , and and the vesicle shape
oscillate (swinging) at middle and high shear rate. In the
oscillatory flow, the coexistence of two or more limit-cycle oscillations can
occur for low in these phases. For the vesicle with a fixed shape,
the angle rotates back to the original position after an oscillation
period. However, it is found that a preferred angle can be induced by small
thermal fluctuations.Comment: 11 pages, 13 figure
Numerical and asymptotic analysis of the three-dimensional electrohydrodynamic interactions of drop pairs
We study the pairwise interactions of drops in an applied uniform DC electric field within the framework of the leaky dielectric model. We develop three-dimensional numerical simulations using the boundary integral method and an analytical theory assuming small drop deformations. We apply the simulations and the theory to explore the electrohydrodynamic interactions between two identical drops with arbitrary orientation of their line of centres relative to the applied field direction. Our results show a complex dynamics depending on the conductivities and permittivities of the drops and suspending fluids, and the initial drop pair alignment with the applied electric field