Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical Engineering

First Advisor

Arezoo M. Ardekani

Committee Chair

Arezoo M. Ardekani

Committee Member 1

John Patterson

Committee Member 2

Pavlos Vlachos

Committee Member 3

Steve Wereley


Swimming motion of microorganisms, such as spermatozoa, plankton, algae and bacteria, etc., ubiquitously occurs in nature. It affects many biological processes, including reproduction, infection and the marine life ecosystem. The hydrodynamic effects are important in microorganism swimming, their nutrient uptake, fertilization, collective motions and formation of colonies. In nature, microorganisms have evolved to use various fascinating ways for locomotion and transport. Different designs are also developed for the locomotion of artificial nano- and microswimmers. In this study, we use several different computational models to investigate the behavior of microswimmers.

Microorganisms typically swim in the low Reynolds number regime, where inertia is negligible. They interact with each other, surfaces and external flow field. Microorganisms often swim in complex fluids, exhibiting non-Newtonian behavior, including viscoelasticity and shear-thinning viscosity. These biological materials contain network of glycoprotein fibers and gel-like polymers. Therefore on the scale of microorganisms, their fluid environments are heterogeneous rather than homogenous. In this study, we develop a computational platform to investigate swimming motion of a single and multiple microorganism(s) in the bulk fluid and near surfaces in complex fluids. We also investigate the role of fluid rheological properties and flow field on the migration of inert particles in a channel flow of viscoelastic fluids.