Fluid Mechanics Seminar: Saverio Spagnolie

It is commonly assumed in the mathematical, biological, and engineering communities that the fluids through which microorganisms swim are classical Newtonian fluids. While this simplifies the mathematical formulation of such problems, many important features of the real physical system are lost. Mammalian spermatozoa, for instance, encounter several complex fluids throughout the female reproductive system, including glycoprotein-based cervical mucus, mucosal epithelium inside the fallopian tubes, and actin-based viscoelastic gel outside the ovum. In such environments even simple questions like ``Do microorganisms swim faster or slower when the fluid is viscoelastic?'' evade simple answers. We will discuss recent investigations of helical and undulatory locomotion in viscoelastic and anisotropic fluids, which can either enhance or retard a microorganism's swimming speed and can even change the direction of swimming! Related topics will also be touched upon, including hydrodynamic entrapment of active particles by colloids, and the transport of cargo by microorganisms in liquid crystals.

Bio: Saverio Spagnolie is an assistant professor in mathematics at the University of Wisconsin-Madison. He received a Ph.D. in mathematics at the Courant Institute of Mathematical Sciences, then held postdoctoral positions at UCSD and Brown University. His research interests lie at the interface between fluid dynamics, soft matter, biolocomotion, and numerical analysis, and he is a co-founder of the Madison Applied Mathematics Laboratory.