title: Reorientation of a nonspherical capsule in creeping shear flow.
abstract: The dynamics of a capsule and a biological cell is of great interest in chemical engineering and bioengineering. Although the dynamics of a rigid spheroid is well understood by Jeffery's theory, that of a spheroidal capsule remains unclear. In this Letter, the motion of a spheroidal capsule or a red blood cell in creeping shear flow is investigated. The results show that the orientation of a nonspherical capsule is variant under time reversal, though that of a rigid spheroid is invariant. Surprisingly, the alignment of a nonspherical capsule over a long time duration shows a transition depending on the shear rate, which can be utilized for a particle-alignment technique. These findings form a fundamental basis of the suspension mechanics of capsules and biological cells.
authors.affiliation: Department of Biomedical Engineering, Tohoku University, Aoba 6-6-01 Sendai, Miyagi, Japan. omori@pfsl.mech.tohoku.ac.jp
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Omori
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Imai
authors.forename: Takami
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Takuji
authors.initials: T
authors.lastname: Ishikawa
mesh_terms: D002214:Capsules; D002468:Cell Physiological Phenomena; D008954:Models, Biological; D008956:Models, Chemical; D008962:Models, Theoretical
chemical_list: D002214:Capsules