Numerical Simulation of the Motion of Inextensible Capsules in Shear Flow Under the Effect of the Natural State. (14th September 2015)

• Record Type: Journal Article
• Authors: Niu, Xiting; Shi, Lingling; Pan, Tsorng-Whay; Glowinski, Roland
• Is Part Of: Communications in computational physics. Volume 18:Number 3(2015:Sep.)
• Page Start: 787
• Page End: 807
• Publication Date: 2015-09-14
• Subjects: 76M10, -- 76Z05, -- 76D05, -- 92C05; Natural state, -- tumbling, -- tank-treading with a swinging mode, -- intermittent region, -- capsule, -- shear flow; Mathematical physics -- Data processing -- Periodicals; Physics -- Data processing -- Periodicals; 530.150285
• DOI: 10.4208/cicp.260714.260315a
• Languages: English
• ISSNs: 1815-2406

Abstract

Abstract: In this paper, a computational model for the natural state of an inextensible capsule has been successfully combined with a spring model of the capsule membrane to simulate the motion of the capsule in two-dimensional shear flow. Besides the viscosity ratio of the internal fluid and external fluid of the capsule, the natural state also plays a role for having the transition between two well known motions, tumbling and tank-treading (TT) with the long axis oscillates about a fixed inclination angle (a swinging mode), when varying the shear rate. Between tumbling and tank-treading, the intermittent behavior has been obtained for the capsule with a biconcave rest shape. The estimated critical value of the swelling ratio for having the intermittent transition behavior is less than 0.7, i.e., the capsules with rest shape closer to a full disk do not have the intermittent behavior in shear flow. The intermittent dynamics of the capsule in the transition region is a mixture of tumbling and TT with a swinging mode. Just like the motion of TT with a swing mode, which can be viewed as a tank-treading with an incomplete tumbling, the membrane tank-treads backward and forward within a small range during the tumbling motion.