Magnetically driven foldable shell type swimmers at Stokes flow

Abstract

This paper focuses on the interaction of low Reynolds number (Re) flows and thin shell type deformable structures in the context of flexible body locomotion and addresses the coupled field problem through a numerical solution framework. The thin structure is discretized by enhanced three-node finite elements and coupled with boundary element based treatment of Stokes flow in a monolithic manner. The locomotion is triggered and driven by an external magnetic field that generates displacement dependent body couples over the magnetically sensitive parts of the flexible structure. A particular novelty of the paper is the use of internal hinges through which very large rotations and structural deformations can be combined in an efficient way. Using this concept; new, on the fly locomotion direction reversal mechanisms can be generated as demonstrated by the foldable bi-directional swimmer.