PIMS/CSC Research Seminar: Gwynn Elfring

The vast majority of organisms, because of their small size, live in a regime where their inertia is negligible. Familiar strategies for locomotion through fluids, such as imparting momentum onto the surrounding medium, are ineffective at this scale due to the dominance of viscous dissipation. Instead, these organisms must propel themselves by other means in this restrictive environment. Moreover, microorganisms such as bacteria often swim in fluid environments that cannot be classified as Newtonian. Many biological fluids contain polymers or other heterogeneities which may yield complex rheology. For a given set of boundary conditions on a moving organism, flows can be substantially different in complex fluids, while non-Newtonian stresses can alter the gait of the microorganisms themselves. In this talk I present a theoretical overview of small-scale locomotion with a focus on recent efforts quantifying the impact of non-Newtonian rheology on swimming microorganisms. Additionally, due to the long range decay of flow fields at this scale, the interaction between multiple swimming organisms can be highly non-local and complex in nature. I will also discuss these hydrodynamic interactions, and will quantify the effects of geometry and elasticity on the collective dynamics of multiple swimmers.

Bio: Gwynn Elfring studies problems in biological locomotion and fluid-body interaction dynamics as well the hydrodynamics of complex interfaces, utilizing tools of applied mathematics and numerical methods for their study. He is presently an Assistant Professor in the Department of Mechanical Engineering and member of the Institute Applied Mathematics at the University of British Columbia. Previously, he completed a Ph.D. at the University of California San Diego and a postdoctoral fellowship at the University of California Santa Barbara.