Date of Award

12-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Committee Member

Dr. Phanindra Tallapragada, Committee Chair

Committee Member

Dr. Yue Wang

Committee Member

Dr. Xiangchun Xuan

Abstract

In recent years much effort have been placed on development of microscale devices capable of propulsion in low Reynold number environment. These devices have potential in biomedicine, micro-fabrication and sensing fields. One of the most promising device that has been extensively studied is magnetic micro-swimmers. Due to small size of the swimmer they operate in low Reynolds number regime. In this case the hydrodynamics is governed by the viscosity rather than inertia. Since the swimmer is so small any kind of motor or other propulsion system is not feasible so we are using magnetic field to remotely control the swimmer. The model used in this work is a simple 3-bead swimmer with a permanent magnetic dipole. Most of the work done using this model shows propulsion in synchronous "in-sync" regime where the dipole of the swimmer is able to follow the applied magnetic field. The nature of motion of the swimmer changes with change in frequency of the applied field. It has been proved that propulsion decreases beyond "step-out" frequency of the applied field. Our work is mainly in the out of sync regime when frequency of applied field is too high for the moment of the swimmer to follow. The existing publication utilizes a non-inertial model (neglects the mass of the swimmer) to predict the locomotion of the swimmer, we also use a similar model for our work. By using a perturbed magnetic field we found propulsion exists in asynchronous regime.

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