| 1 | Hydrodynamic Interaction of Elastic Capsules in Bounded Shear Flow显示文摘This paper presents a modified Loop’s subdivision algorithm for studying the deformation of a single capsule,the hydrodynamic interaction between two capsules and the hydrodynamic diffusion of a suspension of capsules in bounded shear flow.A subdivision thin-shell model is employed to compute the forces generated on the surface of the elastic capsule during deformation.The capsule surface is approximated using the modified Loop’s subdivision scheme which guarantees bounded curvature and C1 continuity everywhere on the limit surface.The present numerical technique has been validated by studying the deformation of a spherical capsule in shear flow.Computations are also performed for a biconcave capsule over a wide range of shear rates and viscosity ratios to investigate its dynamics.In addition,the hydrodynamic interaction between two elastic capsules in bounded shear flow is studied.Depending on the wall separation distance,the trajectory-bifurcation points that separate reversing and crossing motions for both spherical and biconcave capsules can be found.Compared to the spherical capsules,the biconcave capsules exhibit additional types of interaction such as rotation and head-on collision.The head-on collision results in a large trajectory shift which contribute to the hydrodynamic diffusion of a suspension.A suspension of a large number of biconcave capsules in shear flow is also simulated to show the ability of the modified scheme in running a large-scale simulation over a long period of time. | D.V.Le Zhijun Tan | 2014 | Communications in Computational Physics2014，16，9： | 0 |
| 2 | An Immersed Interface Method for the Simulation of Inextensible Interfaces in Viscous Fluids显示文摘In this paper,an immersed interface method is presented to simulate the dynamics of inextensible interfaces in an incompressible flow.The tension is introduced as an augmented variable to satisfy the constraint of interface inextensibility,and the resulting augmented system is solved by the GMRES method.In this work,the arclength of the interface is locally and globally conserved as the enclosed region undergoes deformation.The forces at the interface are calculated from the configuration of the interface and the computed augmented variable,and then applied to the fluid through the related jump conditions.The governing equations are discretized on a MAC grid via a second-order finite difference scheme which incorporates jump contributions and solved by the conjugate gradient Uzawa-type method.The proposed method is applied to several examples including the deformation of a liquid capsule with inextensible interfaces in a shear flow.Numerical results reveal that both the area enclosed by interface and arclength of interface are conserved well simultaneously.These provide further evidence on the capability of the present method to simulate incompressible flows involving inextensible interfaces. | Zhijun Tan D.V.Le K.M.Lim B.C.Khoo | 2012 | Communications in Computational Physics2012，11，3： | 0 |
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