Numerical simulation of single artificial cilium magnetic driven motion in a semi-infinite domain

Abstract

The current paper deals with a completely novel method of fluid manipulation technology in micro-fluidics systems, inspired by nature, namely by the mechanisms found in ciliates. More information on this subject can be found at http ://www.hitech-projects.com/euprojects/artic/. In order to simulate the drag forces acting on the artificial cilium, we have developed a computer code that is based on fundamental solutions of Stokes flow in a semi-infinite domain. The actuation mechanism consists of a bi-directional rotating excitation magnetic field. Two situations have been considered: hard-magnetic material and soft-magnetic for the cilium. In the first case, it was considered that the cilium is uniformly magnetized and immersed in a uniform magnetic field of magnetic density B, such that the magnetic torque on every element of the cilium depends mainly only on the relative position between the element and the constant direction of vector B. In the second case, the magnetization induced by the magnetic field was calculated in a separate routine based on the Integral Nonlinear Equations Approach with 1D discretization of wire (cilium). Distal-end mass flows are computed for several cilium configurations resulting non-zero average mass flow rates. The outcome and originality of this paper consist on assessing magnetic actuation as a practical tool for obtaining a consistent one-directional fluid flow.